Guide to XC Tires:

When to choose light and fast versus on the wider and knobbier?

 

Oh, the dilemma- lighting up your rolling resistance and rotational weight to make the climbs faster versus going for something with a little more bit for spicier terrain. You want traction but you also want light. Let's put in a quick sentence or two introducing you here to set the stage for why people should trust your guide. Something along the lines of, "As a pro XC racer for X number of years, I've tested a lot of different tire setups in a myriad of conditions and put together this fast and easy guide to considering what tires to use for cross-country style riding. 

Cross-country style riding is often done on 100-120mm mountain bikes and XC tires are often chosen to be faster rolling and lightweight. The trade-off is you will have less traction than more aggressive tread tire meant for trickier conditions. There are a few options to consider when choosing your tire setup, so read on to help find your tire match

Choose Your XC Tires

GRAVEL  |  LIGHTWEIGHT XC  |  LIGHTWEIGHT TRAIL  |  CROSS-COUNTRY  |  TRAIL  |  ALL-MOUNTAIN  |  ENDURO  |  DOWNHILL

TIRE WIDTH

Tire Width

First, let’s talk about tire width.  Your rim width and wheel manufacturer will give you guidelines for what tire width is appropriate for your rims.  Most cross-country tires and rims are for the 2.2-2.4 inch tire range.  A wider rim also gives you more volume and more room to play with lowering your tire pressure.  If you’re curious about what tire pressure to run, here’s a guide I wrote to picking the correct tire pressure for the conditions.

SHOP: 32 AX  |  FOX FORK LINEUP

When to choose lighter weight and less width? (2.2 range)

  • Flow trails
  • Lots of dirt road or double track
  • When to run this in a race scenario? When it’s not technical or easy to get a wheel change

When to go on the burlier side of XC (slang term: down-country);  2.3-2.4inch width

  • Loose and steep with bigger rocks (marbles to baby heads)
  • Lots of rocks
  • Wet and rooty
  • Opting for more durability

 

I generally use 2.35 tires for my XC set-up. A favorite combo is the Maxxis Ardent Race 2.35 up front and the Ikon 2.35 in the rear. I’ve also been experimenting and enjoying the new Aspen 2.4 up front.  I also will run the Forekaster 2.35 in the rear when things are wet or particularly loose or blown out on the trail.  I usually do not race the Forekaster because of the rolling resistance penalty.  Wider doesn’t mean you always pay a price for rolling resistance.

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A Word about Tire Casings

First, consider the type of terrain you are riding.  Is it sharp and rocky? How does the terrain change over the season (does it get looser with bigger rocks?). If you are riding a lot of “flow” style trails meaning trails that are high speed but not super rocky or technical, lower profile “semi-slick” tires are fun.  Another thing to note is that sometimes “semi-slick” tires (like the Reckon Race) are not ideal in wet conditions. I learned that the hard way last year at the most technical XC race in BC- the Nimby Fifty where it poured rain.  I won by only a few seconds and hemorrhaged time on the descents from the wrong tire choice.  In dry conditions like my pre-ride?  They would have been fine.   If you want an in-depth view about tire casing and tread, here is a guide I wrote to demystify the world of tires.

SHOP: 32 STEP-CAST  |  FOX FORK LINEUP

Even though I race XC, my style is more like an XC racer with “trail bike” flare and style.  I can mostly (give credit) to moving to BC.  I also specialize in self-supported endurance events.

Here is what I personally consider when it comes to choosing my tire set-up:

I choose 2.3-2.4 tires based on the following (especially as it pertains to racing).  I prefer wider tires because you get better traction and the higher volume means you can run less pressure to grip technical sections better. I typically run the Stans Crest CB7 wheels.

  • My riding style is more trail/enduro but on an XC bike. I also choose to run trail brakes and 180 rotors on my bike which is not really considered a light XC set-up to a lot of people, but I like the control and can gain time on the descents.
  • I do not get to pre-ride a course since my events are so long. I don’t get a preview of the dirt, so I go with what will be best for all-around riding.
  • I do not have support for quick wheel or tire changes like in a lap XC race (and my races typically are not short lap format) If you flat and need a change, you won’t lose much time.  If I do have a flat (and that is very rare), I’ll have to run the same tire for up to 99 miles. Yes, the last time I flatted in a race was a few years about and it was mile 3 of a 100 miler.
  • I go for comfort because I’ll be in the saddle for so long or for many days in a row.
  • I choose on the burlier end of light because of my style of riding. I enjoy to take the A-lines, go hard on the descents, and I don’t want to worry that I’m undergunned.
  • I also choose to run on the burlier side of light because I think you should be very used to the tires you run. The tires you train with should be the tires you race with.  I like to ride the black and double black trails in BC daily as part of my training rides.  As a result, some of the lighter or faster tires are not as ideal.

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Which Tires are Right for You?

There are endless combinations and brands of tires.  There also is no absolute right tire combination.  Everyone has different preferences for ride style.  It’s important to figure out what you like, try to understand why, and maybe even have a few different combinations in your mind for different trail conditions or different times of year.

SHOP: 34 STEP-CAST  |  FOX FORK LINEUP

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CROSS-COUNTRY: 32 FLOAT

Cross-country riding is all about being lightweight, fast and agile. The 2021 Fox 32 FLOAT Performance Grip 29 Fork utilizes a lightweight build and performance technology to achieve a racing quality front suspension. The FIT GRIP 3 Damper uses an adjustable damping lever so you can set your fork to be firm or plush in the travel for increased efficiency. The Fox Float EVOL Air Spring provides increased sensitivity and traction by automatically equalizing the pressure in the forks upper and lower chambers. The performance version is coated with a black anodized finish for a sleek, all-black look.

FEATURES

  • Black anodized finish
  • Float air spring automatically equalizes the positive and negative air chambers for increased sensitivity and traction
  • FIT GRIP 3-position lever with an open, medium, and firm setting

SHOP: 32 FLOAT  |  FOX FORK LINEUP

32 FLOAT FORK SPECIFICATIONS
  PERFORMANCE
Wheelsize Options 29
Travel 100mm
Rake Options 44mm
Air Spring FLOAT EVOL
Damper Options GRIP 3-Pos Lever
Axle Options
9MM Open Dropout
Upper Tube Finish Options Black Anodized
Steerer 1.125 Straight
Rotor Size Options 160 Direct Post Mount, Up to 180 compatible
Color Options Matte Black
Starting Weight*  
* F-S, 32 SC, 27.5", 100mm Travel, Kaboltx110, 3Pos-Adj
Fork weights shown are at 165mm steerer length with star fangled nut and disc brake guide installed.

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FACTORY VS PERFORMANCE   |  STANCHION FINISH  |  EVOL AIR SPRING  |  DAMPER OPTIONS   |  AXLE OPTIONS

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TRAIL: 34 FLOAT

34 is the ultimate trail companion. Featuring an EVOL air spring, choice of dampers, and a lightweight yet robust chassis, you can count on 34 to get up and down the mountain, every time.

Designed for trail riding, the Factory Series 34 features a FIT4 damper, FLOAT EVOL air spring, and lightweight chassis. Starting at only 3.92 pounds, the 34 provides proven trail performance that instills confidence and control.

Trail suspension needs to be versatile, still sporting a lightweight and agile build as seen in cross-country forks, but able to provide more travel when the trail gets rough. The 2021 Fox 34 FLOAT Factory GRIP 2 29” Fork is the definition of a lightweight, trail-quality front suspension. The GRIP 2 version of the Fox 34 Factory 29” 2021 Fork uses Fox’s top-of-the-line GRIP 2 Damper, which provides high and low-speed compression adjustments as well as high and low-speed rebound adjustments. The Fox Float EVOL Air Spring provides increased sensitivity and traction by automatically equalizing the pressure in the forks upper and lower chambers. The Factory version of the Fox 34 GRIP 2 29” Fork includes Fox’s Kashima Coat for enhanced durability and performance

FEATURES

  • Kashima Coat Low friction coating that provides additional durability.
  • Float air spring Automatically equalizes the positive and negative air chambers for increased sensitivity and traction.
  • GRIP 2 Damper High and low speed rebound and compression adjustments provide more sensitivity while maintaining support during aggressive riding.

SHOP: 34 FLOAT  |  FOX FORK LINEUP

 

34 FORK SPECIFICATIONS
  FACTORY PERFORMANCE ELITE PERFORMANCE
Wheelsize Options 27.5 / 29 27.5 / 29 27.5 / 29
Travel 120mm / 130mm /140mm 130mm / 140MM 140MM
Rake Options 44mm / 51mm 44mm 44mm / 51mm
Air Spring FLOAT EVOL FLOAT EVOL FLOAT EVOL
Damper Options GRIP2
FIT4 3-Pos Lever w/adj
FIT4 2-Pos Remote w/adj
FIT4 3-Pos Lever w/adj GRIP 3-Pos Lever
Axle Options
15QR x 110 Boost
15QR x 100
15QR x 110 Boost 15QR x 110 Boost
15QR x 100
Upper Tube Finish Options Kashima Coat Black Anodized Black Anodized
Steerer 1.5 Taper 1.5 Taper 1.5 Taper
Rotor Size Options 160 Direct Post Mount, Up to 203 compatible 160 Direct Post Mount, Up to 203 compatible 160 Direct Post Mount, Up to 203 compatible
Color Options Gloss Orange (29 only)
Gloss Black
Matte Black Matte Black
Starting Weight 27.5* 3.90 lb / 1770 g (F-S, 34, 27.5”, 130mm Travel, Kabolt 110, 3Pos-Adj) 4.19 lb / 1901 g (P-S, 34, 27.5”, 150mm Travel, 15QRx110, 3Pos-Adj)*
Starting Weight 29* 3.95 lb / 1790 g (F-S, 34, 29”, 130mm Travel, Kabolt 110, 3Pos-Adj) 4.26 lb / 1933 g (P-S, 34, 29”, 140mm Travel, 15QRx110, 3Pos-Adj)*
*Fork weights shown are at 165mm steerer length with star fangled nut and disc brake guide installed.  

LEARN MORE

FACTORY VS PERFORMANCE   |  STANCHION FINISH  |  EVOL AIR SPRING  |  DAMPER OPTIONS   |  AXLE OPTIONS

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ALL-MOUNTAIN: 36 FLOAT

The Fox 36 Float forks are built for aggressive all-mountain riding. It features a floating axle offers a distinct performance advantage due to their unique ability to match the exact width of the fork's wheel mounting surface precisely to the front hub flange spacing. This creates a perfect chassis alignment that eliminates unwanted friction between the upper and lower fork legs. The lower legs have bleeders that allow for atmospheric pressure equalization at the press of a button. With the lower leg arch, you'll have enhanced stiffness without the extra weight. All-new design inside-and-out, plus an unmatched combination of smooth performance, tunability, stiffness, and lightweight.

FEATURES

  • Optimized for 150-160mm of travel Fox took the award-winning, EWS favorite and made it even better.
  • Float EVOL technology increases negative air spring volume.
  • Bleeders on the lower legs allow for atmospheric pressure equalization at the press of a button.

SHOP: 36 FLOAT  |  FOX FORK LINEUP

 

36 FLOAT FORK SPECIFICATIONS
  FACTORY PERFORMANCE ELITE
Wheelsize Options 27.5 / 29 27.5 / 29
Travel 150mm* /160mm 160mm
Rake Options 37mm / 44mm / 51mm 44mm
Air Spring FLOAT EVOL FLOAT EVOL
Damper Options GRIP2
FIT4 3-Pos Lever w/adj
GRIP2
Axle Options
15QR x 110 Boost
Kabolt-X 110*
15QR x 110 Boost
Upper Tube Finish Options Kashima Coat Black Anodized
Steerer 1.5 Taper 1.5 Taper
Rotor Size Options 180 Direct Post Mount, Up to 230 compatible 180 Direct Post Mount, Up to 230 compatible
Color Options Gloss Orange
Gloss Black
Root Beer - Limited Edition
Matte Black
Starting Weight 27.5* 4.3 lb / 1965 g  4.3 lb / 1965 g
Features of All 36 Forks Air Channels
Bleeders 
Floating Axle
Mud Guard Mount  

*Fork weights shown are at 165mm steerer length with star fangled nut and disc brake guide installed.

*Not all combinations of travel, dampers, axles, offset options, etc. are available for each color and size of fork.

 

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FACTORY VS PERFORMANCE   |  STANCHION FINISH  |  EVOL AIR SPRING  |  DAMPER OPTIONS   |  AXLE OPTIONS  |  AIR CHANNELS  |  BLEEDERS  |  LOWER LEG ARCH

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ENDURO: 38 FLOAT

Suspension is evolving at a rapid rate and becoming much smoother, stiffer, and more tunable. Modern suspension is more capable than ever before and lets riders conquer the terrain with ease. The Fox 38 Float series forks are hard-hitting, long-travel enduro specialists. It carries over all of the new features of the redesigned 36 and pairs them with the stiffer 38mm to cope with the hardest hits. You'll find the floating axle to match the exact width of your hubs, the lower leg bleeders and the air channels to further perfect your suspension feel. A feature not found on the 36 is the elliptical steer tube that adds material where it's needed, but not where it isn't, to increase strength and stiffness.

FEATURES

  • Optimized for 160-180mm of travel Packing the same revolutionary feature set as the new 36, the category defining 38 is ready for the big time.
  • Float EVOL technology increases negative air spring volume
  • Bleeders on the lower legs allow for atmospheric pressure equalization at the press of a button
  • Elliptical steerer optimizes the stiffness-to-weight ratio, placing more material only where it is needed, and eliminating every ounce of it where it’s not.

SHOP: 38 FLOAT  |  FOX FORK LINEUP

 

38 FORK SPECIFICATIONS
  FACTORY PERFORMANCE ELITE PERFORMANCE
Wheelsize Options 27.5 / 29 27.5 / 29 27.5 / 29
Travel 160mm /170mm / 180mm* 170mm 170mm
Rake Options 37mm / 44mm / 51mm* 44mm 44mm
Air Spring FLOAT EVOL FLOAT EVOL FLOAT EVOL
Damper Options GRIP2
FIT4 3-Pos Lever w/adj
GRIP2 GRIP
Axle Options
15QR x 110 Boost
Kabolt-X 110*
15QR x 110 Boost 15QR x 110 Boost
Upper Tube Finish Options Kashima Coat Black Anodized Black Anodized
Steerer 1.5 Taper 1.5 Taper 1.5 Taper
Rotor Size Options 180 Direct Post Mount, Up to 230 compatible 180 Direct Post Mount, Up to 230 compatible 180 Direct Post Mount, Up to 230 compatible
Color Options Gloss Orange
Gloss Black
Root Beer - Limited Edition
Matte Black Matte Black
Starting Weight 27.5* 4.8 lb / 2180 g 4.8 lb / 2180 g 4.8 lb / 2180 g
Features of All 38 Forks Air Channels
Bleeders 
Floating Axle
Mud Guard Mount
Elliptical Steerer
Air Channels
Bleeders (can be added)
Floating Axle
Mud Guard Mount
Elliptical Steerer

*Fork weights shown are at 165mm steerer length with star fangled nut and disc brake guide installed.

*Not all combinations of travel, dampers, axles, offset options, etc. are available for each color and size of fork.

LEARN MORE

FACTORY VS PERFORMANCE   |  STANCHION FINISH  |  EVOL AIR SPRING  |  DAMPER OPTIONS   |  AXLE OPTIONS  |  AIR CHANNELS  |  BLEEDERS  |  LOWER LEG ARCH

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DOWNHILL: 40 FLOAT

DOWNHILL: FOX 40

Completely redesigned for 2021, the line of Fox 40 forks are built for the most demanding riding conditions from DH racing to park laps to remote freeride. It features a floating axle offers a distinct performance advantage due to their unique ability to match the exact width of the fork's wheel mounting surface precisely to the front hub flange spacing. This creates a perfect chassis alignment that eliminates unwanted friction between the upper and lower fork legs. The lower legs have bleeders that allow for atmospheric pressure equalization at the press of a button. With the lower leg arch, you'll have enhanced stiffness without the extra weight. These forks feature Fox's legendary Kashima coating that provides a buttery smooth feel paired with a GRIP2 damper that provides high and low-speed compression adjustments and high and low-speed rebound adjustments.

SHOP: 40 FLOAT  |  FOX FORK LINEUP

 

40 FORK SPECIFICATIONS
  FACTORY
Wheelsize Options 27.5 / 29
Travel 203mm
Rake Options 48 (27.5) / 52 (29)
Air Spring FLOAT EVOL
Damper Options GRIP2
FIT4 3-Pos Lever w/adj
Axle Options
20 Thru-Axle x 110 Boost
Upper Tube Finish Options Kashima Coat
Steerer 1.125 Straight
Rotor Size Options 203 Direct Post Mount, Up to 230 compatible
Color Options Gloss Orange
Gloss Black
Battleship- Limited Edition
Starting Weight 27.5* 4.8 lb / 2180 g
Features of All 40 Forks Air Channels
Bleeders 
Floating Axle
Mud Guard Mount

*Fork weights shown are at 165mm steerer length with star fangled nut and disc brake guide installed.

*Not all combinations of travel, dampers, axles, offset options, etc. are available for each color and size of fork.

LEARN MORE

FACTORY VS PERFORMANCE   |  STANCHION FINISH  |  EVOL AIR SPRING  |  DAMPER OPTIONS   |  AXLE OPTIONS  |  AIR CHANNELS  |  BLEEDERS  |  LOWER LEG ARCH

FACTORY VS PERFORMANCE  |  FINISH OPTIONS  |  FLOAT EVOL AIR SPRING  |  DAMPER OPTIONS  |  AXLE OPTIONS  |  STEP-CAST  |  AIR CHANNELS  |  BLEEDERS  |  LOWER LEG ARCH

FOX SERIES LEVELS

FACTORY

"Factory" says it all. The best-of-the-best technology Fox has to offer is available in their Factory Series models with the buttery smooth, and ultra durable Genuine Kashima Coat. These products are World Cup proven. You'll find the latest Grip2 damper paired with Factory forks for maximum tuneability.

PERFORMANCE ELITE

Performance Elite forks retain the same adjustments, features, dampers, weight, and 7000 series aluminum upper tubes as Factory Series, but have black anodized stanchions instead of Genuine Kashima Coat; a killer option for those who love a subtle look or are looking to save a few bucks.

PERFORMANCE

Performance Series forks retain the same black anodized 7000 series aluminum upper tubes as Performance Elite, except paired with a GRIP damper making this the most affordable option out of the Fox lineup, but lacking some of the top-end bells and whistles.

KASHIMA VS BLACK ANODIZED STANCHIONS

Beyond the looks, there is one key aspect that sets Kashima apart from it's black anodized counterpart; durability. The friction performance of the two finishes are nearly identical (slight nod to Kashima) and would be hard for most riders to notice. So, why would you want Kashima? That all lies in it's durability. Kashima provides that same low-friction feel for longer with less wear on the stanchion surface. This means less maintenance and better feel for longer. 

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FLOAT EVOL AIR SPRING

Fox's FLOAT EVOL linear spring curve gives forks and shocks plushness off the top, extra mid-stroke support, and more tunable bottom-out progression, allowing riders to tap into the ideal pairing of front and rear-end feel.

EVOL technology increases negative air spring volume, optimizing small bump sensitivity. EVOL’s linear spring curve delivers plushness off the top, extra mid-stroke support, and more tunable bottom-out progression.

The benefits of EVOL are further enhanced by the new Lower Leg channels and Bleeders (found on 36, 38, and 40 forks), which both function to reduce air pressure captured in the lower legs, allowing the EVOL air spring to operate freely without unintended interference.

DAMPER OPTIONS

GRIP2 DAMPER - UPDATED FOR 2021

The GRIP2 damper is the benchmark for unparalleled ride quality and ultra-precise on-the-fly adjustability. For 2021, Fox has taken the GRIP2 to the next level by adding their patented VVC technology to the high-speed compression circuit. VVC is a proprietary variable valve control system that allows for external fine-tuning of suspension performance. GRIP2 achieves with the twist of a knob what typically requires the time consuming and complicated task of completely disassembling and reassembling the fork.

FIT4

In its fourth generation, Fox's patented FIT4 closed cartridge system provides three on-the-fly compression damping positions—Open, Medium, and Firm—to adapt to varying trail conditions. Factory Series forks feature an additional 22 clicks of low-speed compression adjust in the Open mode, allowing riders to fine-tune their exact damping preferences.

GRIP DAMPER

Inspired from moto, the GRIP damper uses the FIT sealed cartridge technology combined with a coil-sprung, independent floating piston. GRIP allows excess oil to purge through specially designed ports at the top of the damper to maintain consistent damping and increase durability. Performance Series forks provide Open, Medium, and Firm modes with additional micro-adjust between settings.

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AXLE OPTIONS: QR VS KABOLT

Many of the forks in Fox's lineup can be configured with either their quick release (QR) style thru-axles or with their Kabolt axle. The QR style axles are very convenient since they don't require any tools to remove them, but they carry a bit of a weight penalty and have the QR lever can be exposed to possible rock strikes if you ride techier and tighter trails. The Kabolt loses the QR level in exchange for using a traditional 6mm hex tool, but shaves weight, reduces exposed parts, and comes in orange or black colors. You will need to be sure to have a 6mm or multitool handy for removing your front wheel, but most riders carry tools on the ride anyway, so it's not a big deal.

FLOATING AXLE

The all-new 36 and 38 come equipped with a new quick-release lever operated patent-pending floating axle system, combining the benefit of a floating axle with the ease of a tool-free quick-release. With this system, axle/hub spacing is locked in via a floating sleeve, allowing repeated front wheel removal and reinstallation while maintaining perfect fork alignment.

Floating axles might look similar to other axles, but in fact they offer a distinct performance advantage due to their unique ability to match the exact width of the fork’s wheel mounting surface precisely to the front hub flange spacing, thus creating perfect chassis alignment and eliminating unwanted friction between the upper and lower fork legs. Floating axles provide much smoother suspension movement throughout the entire range of the fork’s travel, notably improving sensitivity and overall ride quality.

Available optionally is the new Kabolt-X, a lightweight bolt-on floating axle exclusively for the all-new 36 and 38 that not only shaves grams but also increases torsional stiffness via its sleeveless, single-sided pinch bolt design. Chassis alignment must be reset each time the front wheel is removed and reinstalled on both the Kabolt-X and 40 floating axles, but the end result is the same – perfect alignment and perfect performance.

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AIR CHANNELS

As a fork compresses, the air volume within the lower legs decreases, increasing air pressure. The more the fork compresses, the more pressure increases. This effect can have the unintended consequence of preventing full travel from being achieved. The lower leg channels help alleviate this issue by dramatically increasing air volume within the lower legs and thereby reducing the amount of additional unintended pressure ramping.

Another benefit of these channels is that lower leg bath oil is circulated to the upper reaches of the lower legs, continuously lubricating the foam rings and bushings as the fork compresses and extends through its travel.

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LOWER LEG ARCH

Stiffness-to-weight is the ultimate metric for bicycle design. Engineers invest countless hours poring over every ounce of material in an effort to optimize this critical ratio. The all-new lower leg design pulls out all the stops, shaving every possible gram while making sure not to compromise stiffness or strength requirements of modern enduro and gravity style riding.

Modern frame designs and geometry trends require modern suspension design solutions. The arch design of the all-new 36, 38, and 40 is designed to pair perfectly with modern Enduro and Downhill bikes. Head tube profiles have grown larger and larger, and fork offsets shorter and shorter. The new arch shape takes this need into account by jutting forward to provide ample headtube clearance at full compression. State-of-the-art computer modeling techniques helped Fox to create an organic lower leg shape that optimizes stiffness with the absolute minimal amount of material.

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LEARN MORE ABOUT DIALING IN YOUR SUSPENSION

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