Sammyboy

While my Raleigh 20 is off the road, I've been commuting on my Raleigh tourer, and the tyres are just not coping. I'm running 27 x 1 1/4 tyres at 100 psi, and every time I ride it across London, I get a flat. So, whilst I won't be commuting on this forever, it appears that when you've got my 240 lbs, plus a heavy load on the rack, I need some cushier tyres. Trouble is, you just don't GET bigger tyres in 27".

So, I have a pair of medium width 26" rims with cassette hubs which I could throw on there, and then use Schwalbe Big Apples. I realize that the brake reach is going to be seriously different (going from 630 to 559, that's what, 69mm different?), and I'm not sure that's at all feasible. Has anyone tried this? I can get some long reach calipers, 75mm reach, but it strikes me that might not be enough. What are my options? I'm asking here because it's an 80's bike, and because you guys have tried all sorts of things.....

well biked

To use the 559 rims and have the brakes reach, you'll need to be able to adjust the pads down approximately another 35mm (35.5mm is the difference in radius between ISO 630 rims and ISO 559 rims). That's a LOT of additional reach, I doubt you'll find brakes that would do it. What you need to do is measure from the center of the brake mount bolt down to the center of the 27" rims, and then add 35mm. That's how much reach you need to have the brakes reach the ISO 559 rims.

GCRyder

Sheldon Brown has an article on his site about using a "drop bolt" to get needed brake reach for the kind of conversion you're contemplating. It's not very elegant, to say the least. I don't think I'd go that route myself, but it is a solution.

Are you getting pinch flats, or punctures?

tricky 

Disc brakes?

arborohs

which tires have you tried? I use kendas and I think michelin makes a wide 27" tire. Don't know about the michelins but the kendas are dirt cheap.

el twe

You may be able to find a 27x1 1/4" knobby tire, but it would only be marginally wider. A drop bolt sounds like to best solution.

Bill Kapaun

Maybe 590 or 597MM rims (26x1-3/8")? At least you would be closer!
OR 700C rims? I think you can find some 29er tires. Brakes would probably fit OK too.

maureenkh

https://sheldonbrown.com/harris/tires/630.html

This page at Harris Cyclery shows two knobby 27 X 1-3/8 tires that might work. One is the "Cross Terra" by Club Roost and the other is the "Tufflex" by Panaracer.

Maureen

SteakKnifeSally

Unfortunately, the original link is no longer live, because the pictures of a sports with 700c wheels was great, but this cached version captures the text.

Link keeps getting chopped, so google 3 speed update and hit the cached link. Hope it helps.

jgedwa

The real problem may be pedal strike since the bottom bracket is so low. I built up a bike for my gf that involved replacing the original 700's with 26 in tires. The pedals are VERY low. She is riding it now and there have been no problems, and I am keeping my fingers crossed. I could put shorter crank arms on, and maybe find pedals that do not stick out so far, if there is a problem with it.

jim

cooker

Get a beater mountain bike

Sammyboy

I'm not buying a mountain bike! I could go to 700c wheels - to be honest, the only reason for running the 26'ers is that I have a set. I don't think the BB clearance would be SUCH an issue, since with the big, fat tyres I have in mind, the actual rolling diameter would be a lot closer to the original 27"ers. I need to measure my brake reach.

cs1

You're forgetting about BB clearance. Those 26" wheels are going to drop the bike significantly. Your cranks will be a lot closer to bottoming out on the pavement. That's a bad thing. Why not try 650B?

Tim

Sammyboy

I think you didn't read my response. I'm not forgetting BB clearance, I just suspect that it won't be an issue with Big Apples, cos they're enormous. I wouldn't got to 650c because of tyre availability - I don't know how easy it would be to get cushy ones, even online, but I KNOW I can't get them at the LBS. The only reason for considering 26" is that I have a wheelset on hand which will cost me nothing. Otherwise, 700c is the obvious choice, but that just means I can't do it for a while. The 26" solution could happen immediately.

fritz1255

I think you would be going from 630 to 590, or 20mm of radius. Might work just fine with the wheels and brakes that you have. Can't hurt to try. I have done this before, when my 27" got a flat, and it worked (one 26" wheel, one 27"). I can't imagine that 20 mm is going to make any difference in pedal clearance. Not sure how one could work the pedals at all if the bottom bracket were close enough to the ground to scrape.......

well biked

But Sammyboy has 26" mtb wheels, they're 559-

syc

Even if you could get brake calipers that long, it would be a bad idea. You're extending the brake arms by 35mm, which means theres going to be a lot more leverage against the arms. They'll be really flexy and provide poor braking under that kind of leverage. I'm also not sure you could pick up brakes that are long enough to get around a big apple and reach the addition 35mm.

Do you think that Conti Gatorskins in 27 x 1 1/4 would be tough enough for your riding? According to the Harris Cyclery website, they're only about 28mm wide though. They also like the Schwalbe Marathon in that size, and those are pretty durable tires.

Grand Bois

The Panaracer 27X1 3/8 Tufflex tire and some heavy duty tubes seems like the best solution to me. You can get them from any shop that can order from the QBP catalog.

ollo_ollo

While commuting to work(in Olympia, WA) a few Summers ago, I chatted with a guy who rode out from a homeless camp on an 80's road bike which had a pair of 26" mountain bike wheels retrofitted. For braking, he had removed the pads & the calipers just clamped down on the sidewall of the tires. I asked him how well they stopped?? He said "OK if you keep the speed down". (This wasn't a great solution but at least someone has put MB wheels on a road bike).

el twe

Do NOT do that. You're gonna destroy your tires.

ollo_ollo

Like I said, "wasn't a great solution", but I wonder how long it would take to wear through the tire? I did see the guy & his bike around town throughout that Summer. He was usually riding slightly above walking speed.

el twe

I've seen a hole ripped in a sidewall from not even a week of riding like that.

g-funk

I'd invest in some technique. that said I tried to ride a bike in london and gave up in about 10 seconds.

Sammyboy

My technique is generally good. Trouble is, when you're 240 lbs, and you've got a large case with around 20lbs of stuff on the rack (when you hit a bump with panniers, everything gives a little; when it's an Office bag 2 on the rack, it just hammers down), and it's night time on terrible streets - well, I post over most things, but at least once per ride, I lead-arse it through something unwittingly. I'm not really hitting anything hard, if I was, then that'd be my first port of call, it's just that what I'm doing is too much for my tyres. If I can find some 27 x 1 3/8, that may be all the difference. That said, Google cannot find a single UK reference for Panaracer Tufflex

infinityeye

two words.

BMX Brakes.

if in fact BMX is a word...