I’ve recently come into a bit of money and I’ve decided to treat myself to a new propane
Sresh SL E bike (#very excited)
i’ve decided to go with the upgrade of a set of fox factory forks but I’m a bit divided between the 36 and 38
I’ll be interested to know you guys thoughts on which Fork you would recommend.
For reference I am an 80 kg 50 something rider I ride mainly in the tweed valley on the trails and off piste at Glentress and also venture down to the Golfie now and again but I’m definitely not charging hard down the more difficult trails.
Any thoughts you had would be much appreciated
Would it be the latest 36, with the Glidecore spring?
The spec of the two forks seems to be the same both fox factory 160 mm travel - 36/38 mm stanchions Float EVOL spring, Grip X2 damper, Kashima stanchions Adjustment: High and low speed rebound and high and low speed compression
The 38s are generally a little more plush and a bit stiffer, but obviously heavier
For an Ebike, I'd normally say 38 no question and hell with weight, but if you've bought an SL eBike then make weight matters a little to you.
I'd still go for the 38.
I'd go for Swedish Gold version with the Ohlins.
The 38s are generally a little more plush and a bit stiffer, but obviously heavier
When set at 160mm, and with a reasonably light rider, you're more likely to find the 36 more plush, especially if it's the latest version with Glidecore (that keeps the travel smoother if/when the fork flexes). The 38 can feel harsh for lighter riders, with the airspring being too progressive and the chassis being TOO stiff (yes, that is a thing with forks IMHO).
You might struggle to get full travel on the 38 which doesn't seem to be an issue with the 36
The 38 can feel harsh for lighter riders, with the airspring being too progressive and the chassis being TOO stiff (yes, that is a thing with forks IMHO).
Airspring in a 38 is actually less progressive than most... By way of the fact it's a tube inside another tube, it is not compressing the entire volume of air within the outer tube but merely a portion of it, so is actually better than most in this respect...
The new 36 NA3 "glidecore" air shaft really is a significant improvement for the 36 though... I never found a 36 wanting really until I spent time on a 38 and got used to the extra chassis stiffness (I'm mid 90's kg though and riding eBikes almost exclusively these days), and only then did I notice the relative lack of stiffness in a 36 chassis going back to one though. That said, it's not a massive deal, and the NA3 air shaft has really made up for the lack of chassis stiffness in the performance terms (that and 36's tend not to have as much stiction in the bushes as 38's from the factory anyway).
I run a 36 on my SL eBike (albeit it's a 150mm travel) and 38 on my full fat eBike... The Sresh SL looks like it's 150 rear and 160 front, so honestly you could go either way and be happy. How hard a rider are you?
Airspring in a 38 is actually less progressive than most...
If comparing to something like a Zeb, yes. But the question was Fox only, and a lighter rider will find the 38 more progressive than a 36 with the same travel. Noticeably so. Everything in your post is useful and true though.
Airspring in a 38 is actually less progressive than most...
If comparing to something like a Zeb, yes. But the question was Fox only, and a lighter rider will find the 38 more progressive than a 36 with the same travel. Noticeably so. Everything in your post is useful and true though.
I promise you, and I speak with experience here, that the air spring (like for like, same travel) is less progressive on a 38 than it is on a 36 like for like... The simple fact it's running a 34 air shaft in a tube inside a tube, thus only compressing maybe 70-80% of the air volume inside (rather than 100% of it) means it's less progressive in the first place... Of course, a 38 @ 180mm travel will be more progressive than one @ 160mm travel, and likewise it will also be more progressive if chocked full of volume spacers (and they do seem to come with too many fitted from the factory IMO, often 4 OEM on ebikes!) which doesn't help... And yes, you can remove all the volume spacers on a 36 too to make it less progressive... But like for like, travel for travel, my experience is that the 36 is a bit more progressive than the 38, though it does have benefits for the lighter rider (less bushing friction being the big one) too...
I'll see if I can dig out my Shockwiz to measure the compression ratio, but a 160mm Fox 36 with zero volume spacers has over a 2:1 compression ratio (which is still lower than Rockshox) and Fox were keen to make big claims about how much more linear and "coil like" the 38 was when they launched it, albeit it isn't much less progressive (it's still an air sprung fork) but it is a bit less so...
The BIG difference why a lighter rider will get on better with a 36 out of the box vs a 38 is that the 38's typically have a lot more bushing stiction from new... Which isn't ideal whatever you weigh, but the lighter you are, the more you'll notice it. Get those bushings honed though, and it becomes a non issue. It literally then becomes a case of do you want a 2400g fork that is as stiff as you could ever need but that would benefit massively from having the bushings honed from new, or a 2100g fork that is a little bit flexier but (at least with the NA3 air shaft) can be made to work every bit as well up to the 160mm travel limit especially so for a lighter rider.
Either way, if you're a lighter rider, you should DEFINITELY be exploring a slightly lighter oil than the stock Fox 4W in the damper anyway... I'm reliably informed that Fox 4W is just Motorex rebranded, and that Motorex 2.5W is a great substitute for riders who find the stock 4W oil over damped... That or 3W Maxima shock oil.
I've got a Diaz Runt in both my 36 and 38 forks, been running them for years, and they're such a huge improvement both in terms of midstroke support but also allowing you to access all of the travel in a safe and highly tuneable way too... In fact, here's a little video of Chris Porter talking about putting a similar system on Fabian Barel's bike some 15yrs or so ago, before any of the mainstream manufacturers (well I tell a lie, Marzocchi tried it in the early 00's before dropping it) gave it a real go... Now Manitou and Ohlins's major USP is the 3 chamber air systems!
Remember that before the 38 was launched, a Fox 36 was as stiff as you could ever need!
At 75-80kg and 150 or 160 travel the 36 will be ideal.
Thanks for all the great advice
I’ve ordered the bike today and gone with the Fox 36 Forks and teamed this with the fox float rear shock. To continue the fox theme I’ve also treated myself to the transfer dropper post.
#VeryVeryExcited
Can’t wait until the 20th of December when it gets delivered!
Bit late. but for anyone else in a similar predicament
Choose a Lyrik. it's a stiffer and lighter fork than a 36. and also outperforms a top tier Fox fork for the majority of riders who rarely even understand what its added adjustment even does.
Thanks for all the great advice
I’ve ordered the bike today and gone with the Fox 36 Forks and teamed this with the fox float rear shock. To continue the fox theme I’ve also treated myself to the transfer dropper post.
#VeryVeryExcited
Can’t wait until the 20th of December when it gets delivered!
Assuming it's a 2026 model year fork...? If so, it'll come with the NA3 "Glidecore" airshaft in too, which is a real step change in performance for the 36... Especially for longer travel applications. 👍🏻
Thanks for all the great advice
I’ve ordered the bike today and gone with the Fox 36 Forks and teamed this with the fox float rear shock. To continue the fox theme I’ve also treated myself to the transfer dropper post.
#VeryVeryExcited
Can’t wait until the 20th of December when it gets delivered!
Assuming it's a 2026 model year fork...? If so, it'll come with the NA3 "Glidecore" airshaft in too, which is a real step change in performance for the 36... Especially for longer travel applications. 👍🏻
Interesting that's compatible with all post 2021 36's and an easy DIY install as part of a lowers service.
Interesting that's compatible with all post 2021 36's and an easy DIY install as part of a lowers service.
It is indeed... Though Fox/Silverfish are keeping a bit quiet about this at the moment as I don't think they've got much stock of them, and they would rather keep them spare for people who've bought new 2026 forks and need to change the travel than someone with a 5yr old fork that they're happy keeping going for as long as possible...
I've got one in a cheap £250 Merlin Cycles special Performance level fork, and it's amazing! In fact, with 2.5W oil in the damper and the NA3 Glidecore air shaft, its performance level punches way above what the fork cost me...
Fox/Silverfish have been doing a good price on service+glidcore upgrade for 2021+ 36, and promoting it.
I dont see NA3 "Glidecore" airshaft in 170mm anywhere, anyone have a link?
Or is the NA2 almost as good?
I have the cheap merlin 36 too
Fox/Silverfish have been doing a good price on service+glidcore upgrade for 2021+ 36, and promoting it.
Oh ok, didn't know to be fair... I note its absence from their B2B and dealers can't just buy it on its own yet...
I dont see NA3 "Glidecore" airshaft in 170mm anywhere, anyone have a link?
Or is the NA2 almost as good?
The 36 has been 160mm travel maximum for years now... Ever since the 38 came out in fact. A 170mm air shaft was only ever available in the early NA shafts, not NA2 and certainly not the NA3 Glidecore.
And there's a BIG step change in performance (the Glidecore mechanism itself) between the two...
I'd always go for the burlier fork. Lyriks and Fox 36 seem to get creaking CSU even on normal bikes, nevermind ebikes and the associated extra riding / descending etc. Even then my Zeb wore out its non-replaceable bushings (after 3000 miles) and the Fox 38 got the CSU creak after 18 months.
Most 29er Fox 36 can be fitted with a 170mm air spring. The “2026” model released this year (and some older ebike specific models) can’t be. I’m running a NA2 170mm air spring in the chassis that was the current one ‘till March this year. I got the spring from Silverfish and checked with them that my fork would be okay at 170mm. No glidecore 170mm for any 36 though, it’s just 140/150/160, as per the new forks. TFTuned have stock if you can’t get them elsewhere. £135 a pop. Silverfish/Fox are doing a full service plus upgrade to glidecore for £199.
How do you know the improvement was down to the glidecore shaft, and not just a fresh service with new oils? My fork always feels better after a lowers / air spring service.
@mboy do the 36's on Merlin have this new air spring? I gave my damper side stanchion a right going over today after a slide into a wall!
@mboy do the 36's on Merlin have this new air spring? I gave my damper side stanchion a right going over today after a slide into a wall!
The NA3 shaft will only come in a 2026 model fork... So it will depend what model you're looking at I guess. Certainly the cheap paint damaged £250 priced forks I got which are I think a 2024 model didn't come with it fitted, but I added it myself.
You can buy one and add it to any 2021-25 fork...
How do you know the improvement was down to the glidecore shaft, and not just a fresh service with new oils? My fork always feels better after a lowers / air spring service.
Read up on how the NA3 Glidecore shaft works...
You'll understand how/why it makes a difference...
I fitted one to mine after just two rides (having serviced the fork from new anyway, it came with a 160mm shaft and I fitted a 150mm NA2 shaft from new)... I've done thousands of miles on 36's over the last few years, and I'm genuinely impressed at the difference this new air shaft makes!
Thanks mboy.