Hi, first post (sorry it’s a question and not a freebie alert).

I’m converting my 2004 stumpjumper to a 650b (been away from biking for about 10 years). My reason is that I’m replacing the brakes & wheels with a disc setup (still running Vs at the mo), and as I’m building new wheels and not quite ready to buy a new bike I thought I’d experiment with what could be a nice setup for an adventure bike. If I need chunky tires I can always swap the 26″ wheels back on when the trials are muddy.

What sort of rims should I be looking at? I’m not an aggressive rider, but do cwmcarn on occasions. What I want is essentially a comfortable XC bike/light all mountain bike. I’ll be using a 2.2 tire up front and either a 2.1 or 2.0 in the back (for clearance issues), should I be concerned with rim width (would something around 23-25mm be ok)?

Currently looking at the Kore Durox 650b rim (25mm, £62 each). Any other suggestions for about 60 notes (or less even)?

Will a 650b wheel fit an old Stumpjumper? Let alone with chunky tyres.

you’ll probably finder it cheaper to buy built wheels rather than sourcing hubs, spokes and rims separately.

I’d see if a shop’ll let you try some wheels in your frame before you do anything else though.

tbh, and if it were me, I’d stick with the stumpy as is and put all your money towards a new 650B bike with disk brakes and wheels – you’ll find on-one will be abel to do you a complete bike for not much more than you’ll spend on parts trying to get your old bike up to scratch adn replace a few worn drivetrain bits at the same time.

ChunkyMTB, probably not with chunky tires, but according to my calculations it should take 2.0 or even a 2.1 in the back. Fork is fine.

wwaswas, The bike already has a new drive train, plus I have a set of XT hubs and rotors ready for new rims. Just need to buy rims and spokes (I may go with some Mavics as this is an experiment).

As to whether it’s worth it, I like building my own stuff. If this doesn’t work I’ll buy a new 650b frame when their available (like the look on the Rocky Mountain Sherpa demo, but not released yet) and transfer my bits…

fair enough and I hope they fit.

My experience is that Mavic and Stans are good, DT Swiss are made of cheese. 23-25mm (internal) is quite wide so I wouldn’t go beyond that for ‘normal’ stuff.

oh, and bear in mind you may be raising the BB a little if you change diamter of tyres so you’ll feel higher up and handling may be affected as a result of COG changes. Given frame restrictions ( I really would check clearances…) it won;t be by much.

‘Fork is fine..’
Just because the tyre size should fit underneath the arch, doesn’t meant that it will clear the underside of the fork crown, below the headset lower race. If the tyre catches there as the fork compresses fully, then you’ll be exiting over the front straight to A&E…
I’ve recently put 650b rims on our 26″ tandem and with 42mm road tyres, there is precious little spare room anywhere. That tandem was originally designed around 2.5″ tyres, so I’m really not convinced that your plan is feasible.

Oh aye- Rims are Mavic XM319, about £30 each at CRC. With 36h and a quality build, they’re fine on the tandem so far.

on other thing, if you build the wheels with QR XT hubs this is likely to restrict forks you cna use if you do eventually get a 650b frame and fork. Most modern forks above ‘bottom of range’ will have a 15mm front axle and you can’t convert the XT hubs so you’d need to replace.

Cheers guys. If the wheels don’t fit my stumpy then they will just wait for the new frame and fork when I can afford it. If they do fit then I’ll be a happy lad as I love the old stumpy frame (not so keen on the current version, and all soft tails have started to look identical these days…)

23-25 is quite wide you say? Hmm. So, what about the mavic XM319? It’s 19mm and only £30 (plus I have a load of vouchers from tesco for evans who stock them). Do you think 19mm rims with 2.2 techy XC tires is a decent combo?

Ah, cheers highlandman, just saw your post about the Mavics =)

wwaswas, thanks, will bear that in mind concerning the XT QR hubs.

DT Swiss are made of cheese

Thats sooo 2005