Xtrainer suspension help

[Bhamster]

Hi all, new to the forum (New to Beta as well). I took my Xtrainer out this weekend and rode a fairly gnarly section of trail with roots, rocks, and slick mud. I felt like I was getting thrown about on the trial quite a bit. I am a 200# rider and I haven't touched the suspension on the Xtrainer except to set sag. As a reference, I can generally tackle this same section on my 2012 GasGas with marzocchi forks and Ohlins shock without much trouble. But this ride on the Beta left me feeling wiped out like I was fighting the bike the whole time. I have never messed with suspension much, but right out of the gate I wasn't happy with the xtrainer's suspension. So my questions are:
1) would a fork swap to an older set of KYB from a yz125 (as seems to be the preferred system) be better than getting my stockers serviced by AMP? Just to clarify, would a 20 year old set of KYB sprung and revalved for me be equal or better than the stock Xtrainer forks sprung and revalved by AMP?
2) I am deep into this bike financially, so there is no backing out now. . . Without blowing the bank, what shock/fork combo is a good option for general broad conditions (I ride mostly technical woods, but love to open it up when I can)? I live in Washington so 99% of my riding is PNW woods (but I want to make it to the eastside desert soon.
3) I am unclear about forks: I hear things like OC,CC, SSS, etc?
4) I would like to retain the stock wheel and brake if at all possible (I really don't want the bike to look like a franken-bike).
5) How do I determine shock fitting specs? I can't find any information of eye to eye length, stroke length, clamp diameters, etc.

Sorry for being such a scattered mess of questions. It's actually quite exhausting combing through all the different options out there. I really need some simple clarifications and someone to point me in the right direction. Thanks!

[mtdirtbag]

I would make a call to Aaron (the owner of AMP) and discuss your questions, I have found him very receptive to questions and will give you honest answers. He seems to have made it his goal to improve on the XT suspension and from what I understand rides one himself, The prices given on his website seem very reasonable to me.

[wwguy]

The limitations for the Xtrainer's factory suspension are pretty well known, and quite a bit has bit written about then in the Beta internet forums. The inexpensive suspension is the primary reason the Xtrainer is priced $1500 or so lower than the 300RR. Other than physical dimensions and exhaust expansion pipe, both bikes are otherwise fairly similar in design.

What you're experiencing with your Xtrainer is likely a combination of several things:

• The little 43mm forks only have a single spring, located in the righthand fork.
• The fork and shock come from the factory with springs appropriate for 165-175 lbs net rider weight (including gear, pack accessories etc.)
• The forks only have a single valve, located in the left fork, which offers notoriously poor damping control for enduro riding, which in turn results in a tendency for deflection off of trail obstacles.
• The fork rebound damping adjustment via the clicker is mostly ineffective. There's no adjustment at all for compression damping, which contributes towards tendency for the front end to repeatedly dive while braking.

Properly rated springs will set the bike at optimal height to use available suspension travel, and AMP's valving upgrades make notable improvements to stock valving that are sufficient to satisfy the expectations of many riders. But even then, the forks remain limited to a single spring, single valve, and no ability for rider adjustments to compression damping. If you want the characteristics of a full enduro suspension you'll have to replace the stock suspension with something else.

The Xtrainer has a smaller chassis and less suspension travel than other mainstream "full size" enduro bikes, so simply bolting on components from another bike usually isn't feasible. For example the Xtrainer forks are 30mm or so shorter than the 300RR forks, and the Xtrainer shock is shorter too. Most full size forks have 48mm tubes vs. 43mm tubes on the Xtrainer, so an alternate triple clamp is also required for most fork conversions.

The amount of effort required to fit forks from other bikes to the Xtrainer depends on what forks you're using. For example: I'm running a kit on mine that was made by Boano Racing in Italy, who shortened a set of surplus GasGas Marzocchi CC forks by 30mm, provided an appropriate triple clamp to fit them to the Xtrainer's steering head, and provided a brake adapter and axle spacers to match the GasGas fork lugs to the Beta front wheel. Beta USA's Sachs CC fork kit uses a shortened fork from the 300RR, so no axle or brake adapters are required, but it still requires a new triple clamp. Other have built their own kits using shortened forks from other bikes, and adapted the triples, brake, and axle as needed to work with their parts. It all depends on what you have to work with.

Personally I wouldn't waste time or money on fitting 20 year old forks to this bike. "OC" means "open cartridge" design and "CC" means "closed cartridge". You can find plenty of info describing the differences on the web. Either would be a huge improvement over the factory Xtrainer forks, and would likely meet your needs. Beta builds the RR bikes with Sachs OC forks, and the RR Race Edition bikes with Sachs CC forks. Yamaha builds their bikes similarly, depending on whether you're buying a trail bike vs. a race bike. "SSS" is Yamaha's brand name for the KYB CC forks that were first introduced in 2006. I wouldn't consider any Yamaha fork that are older than that.

I'm not aware of any shocks from other bikes that are easily adaptable to the Xtrainer dimensions. As far as I know the options are either upgrade the stock shock valving via AMP etc. or purchase the Sachs upgrade shock offered by Beta USA's suspension shop. They also offer a full upgrade kit for forks and shock, but at $2700 it's pretty expensive.

Hope this helps. As mentioned previously, Aaron Hlad at All Moto Performance (AMP) is a great resource for both consulting and solutions. If you want to put together your own fork kit you might reach out to Steve Beane at After Hours Cycle. He's a Beta dealer and suspension pro who has some experience with this for other riders.

[Lotus54]

A couple of other options:
Beta USA has the ‘Factory option’ of new fork and shock. Rather expensive at almost $2k.
The K9 setup for the stock fork (I have one) and proper spring, this give compression and rebound adjustment.
NOST (N10Z) has a new valving setup for them. I had an old NOST setup on my KTM and it was quite good.

I found the K9 works fine for what I want, but I ride quite slow so called ‘technical’ stuff mostly. I no longer want to ride fast. I have the rebound set fairly quickly, to make it easer to use the suspension for obstacles.
I ordered it with the BYOB when I got the bike, F/R lowered 1”. For your use I would certainly not lower it.

[Bhamster]

If I wanted to cobble together a front end from a YZ, does anyone know what year gives me the correct fork lug offset, brake adapter, and axle diameter? Any thoughts on the adrienni inserts?

I have read all the above and appreciate all your comments. I am working to find a feasible solution.

[wwguy]

If I wanted to cobble together a front end from a YZ, does anyone know what year gives me the correct fork lug offset, brake adapter, and axle diameter?

I just checked my notes from when I was researching this for myself in 2016. I haven't verified any of this firsthand, other than the stock Xtrainer measurements, so take this advice for whatever you think it's worth with that context.

Stock Xtrainer offset is 21mm at the triple clamps and 35mm at the fork lugs, for 55mm total offset.
Stock 300RR offset is 20mm at the triples and 35mm at the forks, for 55mm total offset.

Yamaha introduced the KYB SSS fork in 2006 for YZ125/250/250F/450F.
For 2009 and later the YZ125/250/250F forks were reported to be 5mm shorter than the 450F.
YZ two-stroke triples offset is 22mm for all years, except 2016 where they briefly experimented with 25mm.
YZ fork lug offset is 32mm.

So theoretically a homemade fork kit with 300RR triples and shortened YZ forks would result in 52mm total offset vs. the 55mm factory Xtrainer measurement. I don't know how much this difference would be noticeable to you, if all.

[Bhamster]

If I wanted to cobble together a front end from a YZ, does anyone know what year gives me the correct fork lug offset, brake adapter, and axle diameter?

I just checked my notes from when I was researching this for myself in 2016. I haven't verified any of this firsthand, other than the stock Xtrainer measurements, so take this advice for whatever you think it's worth with that context.

Stock Xtrainer offset is 21mm at the triple clamps and 35mm at the fork lugs, for 55mm total offset.
Stock 300RR offset is 20mm at the triples and 35mm at the forks, for 55mm total offset.

Yamaha introduced the KYB SSS fork in 2006 for YZ125/250/250F/450F.
For 2009 and later the YZ125/250/250F forks were reported to be 5mm shorter than the 450F.
YZ two-stroke triples offset is 22mm for all years, except 2016 where they briefly experimented with 25mm.
YZ fork lug offset is 32mm.

So theoretically a homemade fork kit with 300RR triples and shortened YZ forks would result in 52mm total offset vs. the 55mm factory Xtrainer measurement. I don't know how much this difference would be noticeable to you, if all.

Yeah, I am unclear what effect 3mm in offset will do. Did you find out any information about brake mounting or axle size?

[Bhamster]

SO I was able to find a nice kit that included 48mm marzocchi PFP forks with Boana triple crown, axle, and spacers along with a Fox podium RC2 shock (all set up for an xtrainer I believe from Beta). My question is, the kit is set up for 175lb rider, I am 200 out of the shower. I do mostly slow technical woods and trail riding, should I immediately respring both or try them out first? They will be here thursday and I am excited to throw them on and ride!!!!

[SolidBeta808]

Xt-r Sachs fork swap from beta USA.

[dilyb]

This is an important thread for me and my upcoming '21 XT ... I look forward to learning more about fork (and shock) options!