Not sure if I'm helping with this, but a review I read on the Chisel mentioned that the frame in on the flexy side. It mentioned in a positive tone, flexy=comfortable. For someone at your weight I wonder if the flex would be too much. Overforking it wouldn't help either.

It's also designed as an XC whipet, so maybe not the best choice for trail riding. Something more versatile like a Kona Honzo or a Santa Cruz Chameleon would be my suggestion for a XC\trail ht. A 67-68 deg head angle is a good middle ground for 29ers of this orientation IMHO.

 

Not sure if I'm helping with this, but a review I read on the Chisel mentioned that the frame in on the flexy side. It mentioned in a positive tone, flexy=comfortable. For someone at your weight I wonder if the flex would be too much. Overforking it wouldn't help either.

It's also designed as an XC whipet, so maybe not the best choice for trail riding. Something more versatile like a Kona Honzo or a Santa Cruz Chameleon would be my suggestion for a XC\trail ht. A 67-68 deg head angle is a good middle ground for 29ers of this orientation IMHO.

I'd

Thank you for your reply and opinion, it really puts things into perspective as the thought of it being too flexy has been in the back of my head for a while.

I have also been eyeing the Commencal Meta HT AM Race (https://www.commencal-store.co.uk/meta-ht-am-race-29-2019-c2x26307404). What would be your opinion on it? The tyres seem the widest I would possibly want to go and that much amount of travel seems excessive but I could put a couple of volume tokens in, right?

 

The actual increase in stress on the frame from an increase in fork suspension of 20mm is not really that much. Seeing as the sag would also increase so it would effectively be less than 20mm increase in leverage, and the load is not at 90 degrees so only a portion of the potential increase in torque would be applied to the frame. Unless you are a very hard rider, the odds of it causing any adverse effects on the frame are minimal.

That being said, if the frame was considered flexy to begin with, it would be more flexy with a longer fork.

 

Yeah, I'm now thinking that the added flex would be more of an issue than the stress on the frame.

I'm seriously considering Commencal Meta HT AM Race now but Formula hubs and Powerspline BB has me second guessing. Would it be a good choice for riding in the woods? https://www.commencal-store.co.uk/meta-ht-am-race-29-2019-c2x26307404

 

I was considering the Meta HT AM for myself when shopping for a ht, but the short reach and excessive travel ruled it out. For ht's I think 120-140mm is the sweet spot, remember that unlike fs bikes, only the fork compresses, so the geometry steepens significantly.

I'd throw the Nukeproof Scout 29 as an alternative.

 

Should be fine. For XC racing, I do notice raising the front by 20mm and it has a detrimental effect for climbing steep stuff, enough so that I prefer keeping it at 100/100mm (FS XC racing bike). I have a 120mm fork for that bike for all-around riding and more marathon-type stuff, but for the intense shorter stuff, I'd rather keep it at 100. For all around riding, should be fine, but you may notice it's a bit harder to keep the front wheel down on the steep uphills.

 

I put a 120mm airshaft in my 100mm Reba that was already mounted on a steel HT frame built for a 100mm fork. I liked it better at 120.
I took 10mm of spacer out from below the stem (bar height rose something like 8mm) and rotated the bars *juuuussst a smidge* down to keep the wrist angle about the same.

It's only one data point among a nearly infinite population, but I found no downside personally. The absolute cockpit dimensions changed a litte, bars rose a few mm and got a couple mm closer, but not enough to matter to me.

I recently mounted a Manitou Magnum Pro 100mm with the A2C same as the 120 Reba, and still like it

 

Out of curiosity, why do you want a little more travel? Have you thought about adding an extra token to the fork? It does help depending on what you are trying to do on the bike.

 

I would be okay with 100mm travel but I definitely want more stiffness than 32XC forks offer. So I'm looking into Revelation because of it's burlier 35mm stanchions which, I think, will offer less flex. If the Revelation would come in 100mm I wouldn't be asking this question :/.

 

Thank you all for such informative replies. This was my first post in these forums and you made me feel really welcome.

I think I will be moving away from the Chisel and looking into enduro style hardtails like Nukeproof Scout or Commencal Meta, since weight is not an issue and I'm looking for durability.

 

Thank you all for such informative replies. This was my first post in these forums and you made me feel really welcome.

I think I will be moving away from the Chisel and looking into enduro style hardtails like Nukeproof Scout or Commencal Meta, since weight is not an issue and I'm looking for durability.

Both good bikes, I think you would be happy with either. As far as the idea that the 150mm Lyric is too much fork, just up the air a little and set it so you only use the first 130mm to 140mm, on normal rides if you feel you really don't need 150.

 

I think I might just go with the Commencal and follow your advice to put more air into it. I just learned that it also comes with two bottomless tokens pre-installed in the Lyrik, so that will help too.

 

I think this is a better plan than buying an xc frame and long-forking it. Even if 20mm isn't much of a difference structurally (whether it'll void the warranty or not depends on how forgiving the mfg warranty is), it does much with the geometry. And whether that's a positive change is going to vary from one bike to another, and from one rider to another.

There are lots of good rowdy hardtails on the market these days that it might pay off to take a little bit of time at least, and make some comparisons on paper.

I've got half of a Guerrilla Gravity Pedalhead sitting around while I slowly accumulating parts for a build. Drives me a bit crazy, because I think this is going to be a seriously hella fun bike.

 

On a 26" (wheel) XC racer, I went with a 120mm fork when it was spec'ed for a 100mm.

Granted this was years ago, but I still have that bike, and I totally ruined the ride. It was instantly obvious, and it became an unruly climber, with no apparent benefit on the descents.

I am not saying that this applies to your bike, but with mine it was a huge lesson learned. You won't see me messing with fork lengths unless it's established that it is ok on that particular frameset.

Just my experience.

 

I've increased fork length my 20mm several times. Yes, it is noticeable but not a disaster. You may have to alter the stem length to compensate but if you want to try it, go for it.

 

It's far far apples to apples, but we put a 120mm on my daughter's Gary Fisher Tassajara GS. Originally a 100mm hardtail, womens geometry, and a 26"er. In that case, it works nicely. The resulting change in head angle is great. Bike is more playful, and it didn't get too light on the front end going up steep techy stuff. Going down works better for her as well, as she doesn't need to drop off the back of the seat as much, plus there's the added travel which allows a little more adjustment for subtle stuff. It was a win-win in her case.

 

My 6' 185lb kid has been on a Chisel the last couple seasons. He's never complained it felt flexy.

 

I added a 120mm fork to a steel spot longboard frame that was designed for a 100mm fork. I did alot of research that gave me tons of responses that it would be fine

After half a summer of riding the bike the downtube snapped in half while riding smooth rollers(pump track style rollers). The added 20mm changed the geometry enough that the downtube just gave up and snapped in the middle without any impact.

 

With all due respect, steel tubes do not fail as described above.

 

Now that will break a frame.

 

I've run forks 20mm longer than design spec (100mm on bikes designed for 80) on 2 different bikes (ti and aluminum) for a collective 5000+ trail miles without issue. I prefer the way they ride with the longer forks. YMMV based on your technique, terrain, and bike choice.

 

I'm 25lbs lighter than you, and been riding a Chisel Comp (Large), which comes with a 100mm Judy Gold (a little bit worse than the Reba); can definitely feel the fork flex while riding it aggressively, and it loses performance under heavy breaking (when compared to my full suspension trail bike with a 130mm Pike RTC3).

Also considering to upgrade the fork to 120mm (maybe Fox 34 or Pike), but still unsure if it will void the warranty. If that's the case, I'll get a 100mm SID.

Flex on the frame is not a big deal, I actually think it makes this bike more comfortable (it is really comfortable, even on longer rides...). I don't actually feel that I'm losing any power while pedaling, and even under heavy load, the wheels never touch the frame/brake pads... The Chisel climbs really fast, and is also pretty good on the descents (I feel more confident on the Chisel than on some older full suspension bikes). I'm beating all my Strava PRs on the climbs by ~20%, and I'm ~20% slower on the really technical/rocky descends (when compared to my Santa Cruz 5010).

I'm really happy with my Chisel, and it definitely fits my desired use for it. But if your goal is to decend fast, on technical terrain, would probably go with something like the Santa Cruz Chameleon or Kona Honzo. (Or just buy a full suspension bike)

 

You could get a MRP ribbon sl that is adjustable from 110-130. See what you like. 35mm stanchions I believe and under 4 lbs.