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I own a 2017 Stumpy Here!
I quite like it - although by modern standards, is quite conservative geometry for a 150mm forked bike.
Wondering what I would need to slacken it by 2 degrees? Are anglesets available (for what is a fully integrated Headset?) - I would have no idea what to buy.
It is generally my bike for Welsh weekends and trips to the Surrey Hills. Which seem fewer than before, so would sooner bring this bike to the current day rather than buy a new one.
1 - Can it be done?
2 - How?
3 - Would it ride horribly!?
Thanks!
1: see fresh goods Friday last week!
2: as above.
3: No, it’ll be better.
Have you thought about extending the travel of the fork with a new airshaft.
That's what we did with the one of our Stumpys and also the 2018 Turbo Levo
Have you thought about extending the travel of the fork with a new airshaft.
Personally I'd try the slack headset then the fork increase if I still wanted more.
I had a 2016 stumpy. I thought it was an OK bike until I replaced it and then I realised how bad it had been. The lack of reach was worse for me than the head angle. 6ft3 on an xL stumpy.
Can you fit an offset shock bushing at one or both ends?
Offset bushing for the shock is an option but probably limited to .5 degree.
Shock is a direct mount to the yoke end.
When we were looking we couldn't find anything available that would allow the slackening of the headset.
There is one angleset that works on integrated headsets:
https://nsmb.com/articles/9point8-slack-r-standard-angleset/
I forgot how short old-style bikes were...
The issue with a minus headset is that it'll also reduce the reach and drop the BB (although that might be a good thing). They're cheap enough to try though.
Whatever you do, do not demo a modern bike, unless you intend to buy one.
I had the same model Stumpjumper and upped the travel by 10mm which made it about 0.5 degree slacker. It also raised the BB a bit which was good as I was forever catching the pedals as those bike are pretty low. It was a really good bike for general trail riding and great in the tight singletrack in the woods but don't think I was ever really comfortable on it when things got steep or going flat out. Still a great bike though and I really miss the SWAT box 😀
“The issue with a minus headset is that it’ll also reduce the reach and drop the BB”
Dropping the BB rotates the frame forward which increases the reach, cancelling out the reduction in reach from the offset upper cup.
We have a 2017 FSR 6Fattie with an angleset in in as it came with it secondhand.
It is a low bike already as stock.
It is a lovely bike, very nippy and easy to move around on.
Yes, not ultimately as stable at high speed as newer geometry, but not a 'bad' bike at all.
[url= https://live.staticflickr.com/65535/52483632645_c613a7473b_k.jp g" target="_blank">https://live.staticflickr.com/65535/52483632645_c613a7473b_k.jp g"/> [/img][/url][url= https://flic.kr/p/2nXNku2 ]Laggan MTB ride[/url] by [url= https://www.flickr.com/photos/matt_outandabout/ ]Matt[/url], on Flickr
Speaking as a past owner of a similar Stumpy, there's nothing worth doing with geo changes that don't end up robbing the bike of positives elsewhere. For example, an offset bushing (one is all the bike accepts IIRC) won't do much positive stuff (0.5° slacker ish) and will do some negative stuff too (shorten reach slightly, slacken seat angle etc).
If it were me (and it was) I'd run a short stem (35mm), higher rise bars (50mm), run more sag in the rear (may require putting a volume spacer in the rear shock), and running a firmer fork setup (more LSC and/or higher pressure, vol spacers don't really do anything until the last part of travel so they don't help with general front end support/raising).
Hope that makes sense!
That makes sense @Ben_Haworth - my worry was that in fiddling, I would indeed upset the balance elsewhere! And it does most things pretty well.
Thanks everyone for the info!
New bike time...
New bike time…
New frame time? By the time you spent money on a headset angle, different air shaft, shock mounts, bars. Stem, seatpost etc just buy a newer 2nd hand frame, swop your bits over and sell the stumpy frame.
Will be quicker and might even be cheaper.
If it were me (and it was) I’d run a short stem (35mm), higher rise bars (50mm), run more sag in the rear (may require putting a volume spacer in the rear shock), and running a firmer fork setup (more LSC and/or higher pressure, vol spacers don’t really do anything until the last part of travel so they don’t help with general front end support/raising).
Hope that makes sense!
This was an interesting suggestion... I've got a similar vintage Camber. I don't have issues with the length as I sized up to a Large at 5'10. When I tried a shorter stem I just found the bike felt light, disconnected and twitchy so went back to the stock 70mm. It feels much better, I assume due to the relatively steep head angle.
I think the idea of what @ben_haworth suggested is the bike squats in its rear travel, which effectively drops the BB and slackens the HA while simultaneously stiffening up the early stroke of the fork helps hold up the front more to maintain that stance (sorry horrid word)?
In theory (in my head anyway) you could then run less rear sag + softer front for rutted bridleway xc rides while using the more rear sag and the firmer fork mode for a trail centre day etc. If you tune the shock and fork for the latter then you might find "xc mode" is a bit more compromised (a bit chattery with a lower BB I guess) but get a slightly slacker more stable and optimised experience in "trail centre" mode?
Sorry fork and shock (over)due a trip to the service centre and this has planted a seed of an idea 😁
I've got an older 2015 alloy stumpy Evo 29er, which was probably steeper than your 2017 as stock. SBC's preferred headset size prevented anglesets working (although that Slacker-IS is interesting), so I went from a 140mm fork to 160mm which definitely improved the position and picked the BB up a smidge and reduced pedal/chainring strikes for me (YMMV).
An offset shock bush might be a cheap option worth trying, I've not gotten round to trying one on this frame, it would marginally drop the BB and like with a longer fork will incrementally change reach/seat angle at the same time. All options are a compromise.
One more thought and don't think it's been discussed.
29r wheel ETRTO = 622
27.5 wheel ETRTO = 584
Difference ~40mm => ~20mm top and bottom. A quick measuring tape on two of our bikes suggests a 50mm overall diameter difference on a 2.0 tyre.
If my GCSE maths recall and rough estimation of wheelbase isn't far off then a 27.5 rear wheel should give about 1deg if the OP is running a 29r which I think he is from the link.
On the Specialized seat stay shape that would also give you a little more tyre clearance.