Replace 27" wheels with 700c or 650b? Brakes = Silvers

[cbone97]

So after selling my Sam (sniff sniff), I scored a 1985 Trek 420 with 27" wheels.  It's a beautiful lugged frame that looks like it was barely ridden and I can't wait to get my collection of Rivy parts on it: SunRace thumbshifter (singular, no front der), Dirt Drop stem, fancy drilled Tektro levers, etc.

Here's the hard part.  I'm a hefty lad and need/want a fatter tire than the fattest 27"ers made.  The Trek has a rear hub spacing of 126mm and I don't really want to cold set it to 130mm.  At 126mm, options seem limited to freewheel hubs. I'm ok with that, but all the prebuilt 700c 126mm wheelsets have skinny rims for skinny tires. So it seems I need a custom rear wheel - 126mm hub with a rim that will accommodate 38-50mm tires.

If I'm going to have a rear wheel built on a 126mm hub, would it be preferable to go 650b or 700c?  Can I really get that much more air volume with 650b tires?  My rough measurements suggest that with 700c the rear will fit 38mm tires.  With 700c, I might? even fit a 50mm Big Ben on the front a and a little Ben on the rear.  While 650b theoretically will allow a bigger tire, I'm not sure a 650b Big Ben will fit the rear, which might put me

Assuming that the Silvers will work for either size (reach the 650b rims), which size might be best?  I think either would be fine/ok, am I forgetting anything?  Should I REALLY not rule out cold setting to 130mm and going with a freehub wheel?

Thanks!

[Kurt Manley]

I don't know about the 650b compatibility but I will say that in my opinion if you're a heavier rider it is a waste of time to build a wheel around a freewheel hub. They are by design much weaker than a 130 cassette hub. I weigh 240 and have killed more than a few freewheel hubs by breaking the axle, the weak point of those hubs. You can usually just squeeze a 130 hub in a 126 frame although cold setting is easy and worth it.

Good luck with the new frame!

[franklyn]

With a steel frame, you don't really need to cold-set the frame from 126mm to 130mm. My wife recently acquired a 1983 Trek 500 and we modernized the parts and use 130mm OLD ultegra/A23 700c wheels. The frame has 126mm but a gentle tug east-west of the drop-out allows me to pull the rear wheel in easily. 

Actually, the Silver/Tektro 559 might not work with 700c wheels, unless the reach for 700c on the frameset is longer than 55mm. So you really need to determine the wheel size first before selecting the brakes. Also, unless you can score brakes that uses nut instead of recessed allen, you will have to drill the frameset to use most recess-allen-equipped brake calipers. I tend to use center-pull brakes for these conversions for easy and inexpensive sourcing, as well as better braking power.

Franklyn

On Thursday, August 28, 2014 5:03:39 PM UTC-7, cbone97 wrote:

[Chris Chen]

Remember that you'll be dropping the bottom bracket quite a bit if you go to 650b. 700 sounds like a good place to go.

Granted, if you put FATTYS with 650b then you don't drop all that much but you get my point.

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[franklyn]

BB drop is a concern, but if you look at the geometry of these old Trek road bikes their original BB drop is in the low 70s, which makes them good 650b conversion candidates--and therefore you will see many examples of old Trek 650b conversions on the internet. Given that you will be using at least 38mm wide tires compared to the 23mm 27" tires, the final BB height would be pretty close.

Franklyn

[Bill Lindsay]

I'm with Christopher.  700c is where I would go.  If you know 700x38 will fit, get some C-lines and you are DIALED.  

On Thursday, August 28, 2014 5:14:12 PM UTC-7, Christopher Chen wrote:

[franklyn]

actually, since the old 27" tires were most likely measured no more than 25mm wide (even if they were marked 1 1/8 or 1 1/4), going to 38mm 700c tires actually raise the BB height noticeably. 650b/38mm tires are likely to be closer in wheel/tire diameter to 27/25mm than 700c/38mm.

Franklyn

[Eric Daume]

I'm skeptical you could fit a true 700x38 in there. On my '83 620, I have good clearance with an actual 32mm tire (Performance Metro "35"), but not enough room for a fender. On a previous 27" --> 700c conversion (an old Fuji S10S), I could fit a true 35mm Pasela in there, but it was nearly scraping the brake caliper undersides.

On Trek conversions I've read about, most folks struggle to fit a 42mm Hetre in there. 650B x 38mm is an easier fit, which I think typically also allows for fenders.

Eric Daume

bikingtoplay.blogspot.com

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[Steve Palincsar]

On 08/28/2014 08:20 PM, franklyn wrote:
> actually, since the old 27" tires were most likely measured no more
> than 25mm wide (even if they were marked 1 1/8 or 1 1/4),

Not when I was using 27 x 1 1/4" tires, they weren't no more than 25mm
wide.

[Jim Bronson]

New nutted brakes are not difficult to find.  Don't drill the frame.

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[Jim Bronson]

I agonized over these numbers for months before converting my older Rivendell custom to 650b.  Why speculate?  It's 23 mm lower to go from 630 (27") to 584 (650B) whereas it's 19mm to go from 622 (700c) to 584 (650b). 

So, there's not much difference between a 27" to 650b conversion and a 700c to 650b conversion.  Less than half a centimeter.

Some of the distance will be made up by the larger tires, so there's that as well.  Someone else said BB drop was in the lower 70s on your Trek so you're in better shape than I was with 80mm drop.

Many old Treks have been converted to 650b and AFAIK most owners have been happy with them.  There's pictures all over the Internet.

If you are absolutely sure that a 700c x 38mm tire will fit, then 700c could be ok, but if there's any question, go 650b.  I did and I have been very happy running 650b x 38mm Compass LoupLoup Pass.

I'm also a really big guy and i recommend staying away from Velocity Synergy rims.  Had to send one back with cracks along the spoke holes.  I've had good luck with their Atlas rim so far though that they rebuilt the wheel with.

[Michael Hechmer]

I have a 1984 Trek 620,which I bought after selling a1983 Trek 620.  The 84 model was specd with 27" wheels and canti brakes set just at 57 mm drop.  I first converted to 700C and found that I could barely fit a 30 mm tire (actual) and fenders.  I ground out some metal at the bottom of the crown to make it work.  I did spread the stays to 130 mm.  No problem.  I really like the way the frame handled and responded.   Beautiful.  I found the ride responsive and didn't want to let go of it.  So I had it repaired and the studs repositioned for 650 B, along with S&S couplers.  Now I ride it with 38mm Pari Moto tires and absolutely love it.  A good ride is better than a vintage show piece.

I think the 420 is one level down in steel and components (now probably long since gone) but I'll bet that good Reynolds standard gauge steel still performs wonderfully.  I'd say go for a modernization. Spread to 130, easy.  Convert to 650B.  A bargain compared to any new, comparable frame.

michael

[Eric Daume]

This really makes me ponder converting my Trek to 650B. Man, I was so close to having one wheel size for my bikes!

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[DS]

I converted a 1984 Trek 500 to from 27" to 650 a few years ago. Was able to fit 650 x 38 tires, I don't think I would have had clearance for anything larger. I believe that was also a 126mm hub and I had no problem sliding a 130mm hub in there. There was just enough reach on the brakes with the Tektro long reach brakes. No issue with the bottom bracket difference. I liked that setup a lot. Sold it to my brother though. Looks like the vintage-trek.com site is down, hope its temporary. If I ever doe another 650b conversion I'll look for a similar trek bike.

[David Hays]

Were you able to fit fenders with those 650 x 38 tires?

On Aug 28, 2014, at 11:03 PM, DS <davec...@gmail.com> wrote:

I converted a 1984 Trek 500 to from 27" to 650 a few years ago. Was able to fit 650 x 38 tires, I don't think I would have had clearance for anything larger. I believe that was also a 126mm hub and I had no problem sliding a 130mm hub in there. There was just enough reach on the brakes with the Tektro long reach brakes. No issue with the bottom bracket difference. I liked that setup a lot. Sold it to my brother though. Looks like the vintage-trek.com site is down, hope its temporary. If I ever doe another 650b conversion I'll look for a similar trek bike.

[Michael Hechmer]

I don't have fenders on my Trek 620 but could fit them around the 38mm pari mottos.  I don't think it would work with 41s though.  The chain stays are too close.  Also those bikes have horizontal drop outs so you would want that spring mount that VO sells.

Michael

[jtallman]

I bought a 1985 Trek 400 earlier this year, and it has become my favorite bike. It looked unused, with just a few marks on the paint from where it was moved around in the garage over the years. According to the 1985 Trek brochure, geometry for the 400 and 420 are the same, and the tubing set is the same. Both came with 27 x 1 1/8 tires and the same DiaCompe brakes, so tire clearance may be similar.

I replaced the 27 inch wheelset with 700c. The rear hub is 130 and fits fine as is, no problems. The tires are 33 mm Jack Brown Greens. No way a bigger 700c tire would fit. Pretty tight at the chainstays and even tighter under the fork. I actually tried a Pasela 27 x 1 1/4 first and they were too big.

I installed 2 Tektro R365 sidepull brakes from Riv. Both are front recessed brakes. The fork on my 400 is recessed and the rear brake bridge is not, so a few washers on the rear and the brakes worked fine. The 700c wheelset has the brake pads at the top of the slots. A 650b wheelset would probably work with these brakes.

Pictures of my Trek 400, with several Riv upgrades, here https://flic.kr/s/aHsjXsYBGU

Good luck!

On Thursday, August 28, 2014 8:03:39 PM UTC-4, cbone97 wrote:

[Tim Gavin]

My Riv Road has very similar clearance to steel Treks and other classic sport touring bikes (on purpose).  With a 650b conversion, the limit became the width of the chain stays and fork legs, not the height.  I have plenty of extra height for fenders above 650x38b tires, but no width clearance for Hetres.

SKS P45's fit great.  I improvised a spring mount for the front fender so I can remove the rear wheel (horizontal dropouts).

I converted an '84 Raleigh Marathon from 27" to 700c, and it clears a 700x32c tire but would not fit a bigger 700c tire.  Considering it was designed for 27 x 1 1.8 (28 mm) tires, that makes sense.  There is barely enough space under the brake bridge for a P45 fender.  It fits, but tightly, so the fender line is kinda crummy.

I also have a pretty minty '85 Trek 420 that I scored for $100.  Nice brazing, good looking frame.  But mine is too small for me, so I'm gonna sell it to a friend and help him build it up into a tourer.

If you want >32mm tires and/or fenders, you should probably go with a 650b conversion.  Tektro 559 brakes come in nutted mount versions.  If you're ok with 32 mm tires and maybe fenders, then 700c should work fine.

[cbone97]

Thanks to everyone SO much for all the helpful info.  I never considered that I might be tire height limited with 700c.  Guess I'll pursue 650b wheels and see how bigga tires I can squeeze in.  My 420 is the 24" frame size so hopefully I can go a little bigger than 38mm.  Will post before and after pics when all done.

[Peter Adler]

I'm attempting a similar 27"-to-650b conversion at the moment, with Silvers on a 1972 Raleigh Super Course. Early indications are that 700c is fine, but there may not be enough reach to make it out to 650b. As for the nutted brakes: I picked up my recessed Silvers at a Riv garage sale a couple of years ago (missing the attachment fittings for the QRs, which I cannibalized off salvaged brakes from bike kitchens). At the last Riv garage sale in July, I found several pairs of huge Tektro sidepulls that Grant IDed as parts for some abandoned project; Tektro lists them for beach cruisers. Fortunately, they had nutted bolts, and Riv was selling them for $5/pair. The bolts were not easy to get out of the brakes, but they fit the Silvers just fine.

Peter in Berkeley

[cbone97]

SOOO strange you should mention those huge beach cruiser Tektros.  I had just ordered a front one from Amazon to try a 27" to 26" conversion after popping a front rim/tire on the 420 and thinking "why not?".   It looks like it'll work great and let me put on fatter tires than I could with 700c or 650b so I'm a little surprised I can't find any such conversions on the google.  If the big Tektro brake isn't total crap I'll be ordering the rear and having a custom 130mm rear wheel built.  

[Peter Adler]

The specific model is Tektro C324, with 98-116mm reach. If you decide to get more, you might want to call Rivendell; they had a case at the sale, and as near as I can tell, I was the only one who bought a set. They might be grateful to sell another.

Or you could get back to me; I'm assuming I'll never use the now-recessed front, which should work fine for a nutted rear. They seem like pretty wussy brakes - good enough to stop a cruiser, but not quick enough to stop anything moving at speed. If the Silvers don't make it, and I can't find a serious sidepull that gives me the necessary reach, I'll switch back to G_d's own brakes - centerpulls (Weinmann or Dia-Compe 750s, whichever comes to hand first).

Peter

[Johan Larsson]

On Friday, September 5, 2014 5:47:05 AM UTC+2, Peter Adler wrote:

The specific model is Tektro C324, with 98-116mm reach. If you decide to get more, you might want to call Rivendell; they had a case at the sale, and as near as I can tell, I was the only one who bought a set. They might be grateful to sell another.

Or you could get back to me; I'm assuming I'll never use the now-recessed front, which should work fine for a nutted rear. They seem like pretty wussy brakes - good enough to stop a cruiser, but not quick enough to stop anything moving at speed.

Could you please let us know how these brakes turned out when you have tried them? They look flexy, but it's impossible to know for sure how they work until they are tested with some good brake pads.

Johan Larsson,
Sweden
 

[cbone97]

The brakes I'm looking at cover 79-99 mm, at least according to Amazon's description.  I need about 89mm reach so they should work.  Amazon lists models 324 and 326 on a search, but the model isn't in the description of the brake I've ordered.  Thanks for the offer on the brake, I may contact you offline if what I have on the way doesn't work.   If a 27" to 26" conversion is possible with either brake, this could be good news for Riv types on a budget.  I'll post the results / pics.

[David Hays]

I switched a Raleigh Marathon Mixte from 27" to 650B with Silvers and had no problems. Plenty of reach.

My LBS did a great job of coldsetting the rear triangle to 130 for me.

David Hays

Kenmore, New York