Bicycle Mechanics - 700C/27" roadie wheel sets?

After searching the archives, I still don't know the answer to this question.
Shelton Brown suggests that there is only an 8mm differenace between traditional American 27" wheels and the 700c wheels.

So the question is... Are they interechangable?

I have older roadie that I am looking to put new a new wheel set on.

Thanks

Yes and no. If you have newer wheels, you may have to spead the rear triangle to accomodate the hub's width. You also may have to change the brakes to compensate for changes in reach. Tire clearance itself shouldn't be a problem.

You can interchange the tubes, excpet latex, but not tires.

I bought an old road frameset designed for 27" wheels but built it up with 700C. It required long reach brakes anyway but with the 700C wheels, the brake pads are very near the bottom of the adjustment. The difference at the brake pads is only 4mm.

I would think that 27" wheels in a frame designed for 700C would have tire clearance problems. Some frames designed for wide 700C tires might work with a narrow 27" tire - say a 27x1".

Thanks to everyone for your replies.

It looks like I can replace my 27" wheel sets with 700c if I have to.

The only reason I am thinking of doing this is the lack of 27" wheel sets I have been able to find. The old girl currently has the original chrome wheels which offer little to no stopping power during wet riding conditions. That combined with their age drives my quest to replace them. If I didn't mention it before, the bike is a 1978 (or so) Raleigh Grand Prix. It is a blast to ride.


Thanks again!
Bob

Yes... If you can fix the brake problems then you can do it.

The comment about wider width of the axle is really only that a comment. You can always rebuild a wheelset using your existing hubs and 700C rims. That will solve the axle width problem.

Of course if the hubs are worn out then you may have fun finding new hubs and then the axle spacing problem will be at hand.

I guess the dropout width/axle length comment was assuming he might be going from a 5 sp rear with 126 mm spacing to a 9 sp freehub setup w/130 mm. Since this is probably an older steel frame the 4 mm shouldn't be a problem.

I guess the dropout width/axle length comment was assuming he might be going from a 5 sp rear with 126 mm spacing to a 9 sp freehub setup w/130 mm. Since this is probably an older steel frame the 4 mm shouldn't be a problem.



Sorry there, Mr. Cellophane, but 5-speed hubs were 120mm, not 126. 10mm often is a fairly big deal.

I would be happy with keeping the original gears. I have not even thought about upgrading them. What would be the bennies of going to a 7 or 8 speed gear set?

To clairify, this is a late '70s Raleigh Grand Prix. Steel frame.

The axle spacing they are talking about is your limiting factor...

The 5-speed (and 6 speed?) is like 120mm
8/9speed is 130mm
7 speed is 125mm.

Typically the rule is if your bike is steel then you can get away with one size larger without modifying the frame. The wheel is a bit tough to fit as you will have to pull on the frame to get the axle to drop into the dropouts (into the outs... :)

Going from 120 to 130 is too much and a good shop could bend the frame to accomodate but typically it is not worht it... Also cannot modify aluminum or carbon (or Ti?)

If 7 speed is 125mm and your drop outs are at 120mm then you could do that. 7-speed wheels are still fairly easy to get.

If you go 7-speed, try to stay Shimano and locate 7-speed shifter and rear derailleur. Otherwise you may have to go to friction shifters.


If you are a bar-end shifter guy, 8-speed shimano shifters will work... Same spacing/index as 7-speed... Just one extra click you won't use :)

What would be the bennies of going to a 7 or 8 speed gear set?

More closely spaced gears. You can also get taller gears as most 5 and 6-speed freewheels start with 13T or 14T but you can get 7 and 8-speed cassettes that start with 11T or 12T.

If the rear hub is 120mm/5-speed, an Ultra-6 speed freewheel will fit.

If the rear hub is 126mm/6-speed, a 7-speed freewheel will fit.

Wow, the more I read, the more I think I'll take the bike into my LBS. At least now I know enough to talk with them so we can understand each other... :D

If the 4mm radial difference between 27" (630mm diameter) and 700C (622mm) rims is too much for your brakes, you can get a drop bolt from Sheldon or a longer set of brake calipers. My only remaininng 27"-wheeled bike is the Peugeot UO-8, which appears to have just enough brake slot length to handle 700C rims.

In the old days, I had two sets of wheels, 27" clinchers and 700C tubulars, and my Nishiki Semi-Pro and its Diacompe (Weinmann Vainqueur 999 clone) centerpulls had long enough slots to handle the wheel swaps.

Hey lookie what I found! Shimano 105 hubs... 7-speed! 126mm!!!!

Oh BTW my shifter comment shoulda been: You can use 8-speed Shimano shifters (all kinds) on the 7-speed <same spacing between gears> you will just have an extra CLICK you won't be using :)

Here is the link to the hubs:

http://www.thethirdhand.com/index.cgi?d=single&c=Hub&sc=Complete%20Hubsets&tc=Cassette&item_id=SH-1057HS&id=543022512424

N7CZ...if your in the flat part of Montana a 5 speed may work OK for you.

Your can use a 130mm hub in a 120mm steel frame.....its only 5mm per side. If you do it the dropout faces will need to be re-aligned.

And seriously.....Sheldon 'wheels' Brown has alot of mis-information on the Harris Cyclery website. Most of its in the 'wheels' section.

I don't think I would want to do 5mm per side. Converting my DuoSport tandem from 6-speed to 7-speed was bad enough... (6mm or 3 per side)... I nearly pinch my fingers every time I try to repare a flat on the road.

Just dealing with the extra tugging on the frame just to get the wheel into the dropouts is not worth it IMHO.. Make the differnce 10-12mm and I could get very frustrated on a day with multiple flats..

Preston, I understand what your saying about pinching your fingers. If you 'cold set' the rear stays its not a problem....

Did I ever tell you I live a block off of A1A??.....(inside joke)

Yea that's if you got the jigs to pull on the frame :)

Hey did you do the "Kids in Distress inlet challenge?"

Man that ride was pure torture. They were screaming-fast the entire way.

You might check a few thrift stores. In my area there are still lots of basically unridden bikes with 27 x1 1/4 or 1 1/8 Araya rims laced onto Shimano or SunTour hubs. I frequently paid $9.95 for the entire bike & there are other good parts on some. They woould be fine for your bike. Don