Cyclocross tyres in 26x1 3/8 size???

GarethPJ

I think the 650a will continue for years to come, if only because Schwalbe continue to make some top quality tyres in that size.

Cycle Speedway helps too, as in most disciplines one particular rim size is perceived to be the best, and in this case it's 650a. Because of this there is plenty of demand for rims and tyres, particularly since the only speedway specific tyre is in the 650a size. In this respect the fact that the sport is quite low profile is probably a good thing. If the sport had a wider following then the major manufacturers would probably start making bikes, and then they'd probably want to move to 622, 559 or maybe 584 wheels.

I've always fancied a cycle speedway bike for the road, I would however like to keep the minimal brakeless look. I've often thought the best way to achieve might be to fit drums. Maybe using short BMX style brake levers wouldn't show too much, and some cunning internal cable routing should keep the lines clean (front cable down the steerer?). Or maybe a coaster at the rear? Why not a fixed, well speedway bikes have freewheels so to my mind a road going version should have one too.

stickman

Do you know of any new 650a bikes being made apart from speedway?

The junior speedway bikes have 24x1.75 wheels, lets hope the rest of speedway stay with 1 3/8.

Drums sound good for a street speedway bike, no rim wear and all weather constant performance. I had a Sachs coaster brake on my beach cruiser and it was poor from new and got worse over time, don't know if they're all like that.

GarethPJ

I'm told there are still three speeds coming out of China with 650a rims, I don't know of any more mainstream sources. However it's worth bearing in mind that since many mainstream western brands have their bikes built in the ROC these bikes could be coming out of the same factories as some familiar brands.

What about Pashley? Or have they yielded to the tide and started fitting 622 or 559 wheels. Actually I don't care if they have, I still want a Guvnor, single speed of course.

stickman

There's the domestic market of Japan where 650a is supposed to be big, I don't know any details though. We need Japanese imports!!!

I love the Pashley Guv'nor. The wheel size 28x1.5, I think all their roadsters are. Don't know what size the Tube Rider is.

stickman

I was due to get my 3 speed 650a today, I got a phone call today telling me they were not able to get one so that's the end of it! Only cycle speedway now. Do any frame geometry experts out there know if they are good for cyclocross?

GarethPJ

As far as I recall CX bikes tend to have similar geometry to that of a road bike, maybe with a slightly slacker head angle. I'm sure Archie Wilkinson will be happy to tell you the geometry of his frames. I don't expect that they are particularly radical since old rigid MTBs do pretty well in cycle speedway.

stickman

I cut a piece of paper out in the same shape as a speedway frame front triangle and put it over some cx bike pictures and they seem to be the same. The cs forks have no curve though.

stickman

I found this: http://www.geocities.com/ovalking/FrameGeometry.GIF

(An Archie Wilkinson bike)

GarethPJ

I've been thinking about this and the biggest problem you will have is the brakes. My concern would be that the speedway frame has not been built with braking loads in mind,

People have been known to fit 700c rims in rigid MTBs to make a CX bike. Mavic used to make an adaptor bridge that moved the canti bosses up by 30mm or so. That would be too much for 650a rims, however the other way to do it is to use cantis or V brakes with long enough pad slots to compensate for the bigger rims. You need to raise the pads by about 16mm over a 559 rim. I seem to recall there were some Dia Compe mini V brakes with long enough slots to accomodate a 700c rim in an MTB frame! So they would definitely do the job with 650a rims.

Good quality old rigid MTB framesets can be had for pence these days. Something in a good tubeset can often be had for under a tenner, I had an old 501 Raleigh frame and fork for £3 a few years back.

stickman

I've been thinking the other way about the Archie bikes, because of the caliper fixing holes, that they order regular frames from a builder and spray them to their own design and add the components to turn it into a speedway bike. I think they look like a cx frame with a dirt jump fork and cruiser handlbars! I like the idea of an alloy frame and 650a wheels but i've made no definate decisions yet, i've been looking out for 2nd hand bikes and thinking about converting my singlespeed to cx but then i'd lose my rain bike and a nice commuter!!!

mz__jo

I think that 650B rims will be accomodated by V-brakes in a mtb frame. It looks that way and some day soon I will try fitting the tandem's wheels into the mtb to prove the point. However it may be only just and I wouldn't guarantee 26 x 1 3/8. The extra 3mm may go easily or may be the difference between success and failure. May have a go at it next w/e, I need to take the rear wheel out to change the brake shoes on the tandem.
Cheers Jo

stickman

I decided to use my singlespeed for cx, i'll make my cruiser into a rainbike. I ordered a 38 tooth alloy chainring and cranks to replace 46 tooth steel, the rear is 18t, and I ordered a pair of Schwalbe CX Pro 26x1.35 tyres as it has mtb rims.

I'd still love to get an Archie as a street bike one day though.

stickman

There's an Archie Wilkinson currently on ebay, only a child/teen size but interesting to see.