dooley
10-30-05, 03:12 AM
I run a 5 speed 14-28 shimano freewheel at the moment and fancy getting a shimano 11-28 7 speed, my only concern is wheel dishing. How much wider than the 5 speed is the 7 speed?
Bicycle Mechanics - Going from 5-7 speed...
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sydney
10-30-05, 07:45 AM
Duno that it mattters if you use a dishing tool. you may also have to widen axel spacing as OLN was typically 120 for 5 speed and 126 for 7 speed.
askrom
10-30-05, 08:58 AM
Dooley, if you can find that shimano 11-28 freewheel, please let me know because I can't find it in stock ANYWHERE. Thanks!
dooley
10-30-05, 09:02 AM
So 6mm then? Thanks.
It's just that I want to use minimal dishing.
It's just that I want to use minimal dishing.
grolby
10-30-05, 03:53 PM
So 6mm then? Thanks.
It's just that I want to use minimal dishing.
Not necessarily. The 6mm difference is in the Over Locknut Distance - the distance between the two points on the axle that fit into the bicycle's dropouts. The OLD of your rear wheel axle and the spacing of your frame's rear triangle must match or be very close (within 2mm or so) for the wheel to fit the frame.
When seven speed freewheels were introduced, they were intended to fit on an axle with 126mm OLD, which fit frames with 126mm spacing. A five-speed wheel will have an OLD of 120mm. There are two main implications to all this:
1. In order to upgrade to seven-speed, you must re-space frame, through cold-setting (translation: bending it). If you don't have a steel frame, this is inadvisable, and you're really stuck with five speeds.
2. You will indeed need to re-dish the rear wheel, although not necessarily by 6mm. That has to do with a combination of the new OLD and difference in size between the five and seven-speed freewheels. In fact, I would hope that you don't have to re-dish by as much as 6mm - you are adding two cogs, sure, but the space between the cogs is also significantly reduced. I really have no idea, but I would hazard a guess that you won't need to change the dish by any more than 4mm or so.
This is, of course, assuming that your current hub and axle will fit a frame with 126mm spacing. It isn't guaranteed. It isn't necessary to buy a new hub, but if the axle is too short... good luck finding a replacement. You might just want to buy or build yourself a new rear wheel. Good luck with this project!
It's just that I want to use minimal dishing.
Not necessarily. The 6mm difference is in the Over Locknut Distance - the distance between the two points on the axle that fit into the bicycle's dropouts. The OLD of your rear wheel axle and the spacing of your frame's rear triangle must match or be very close (within 2mm or so) for the wheel to fit the frame.
When seven speed freewheels were introduced, they were intended to fit on an axle with 126mm OLD, which fit frames with 126mm spacing. A five-speed wheel will have an OLD of 120mm. There are two main implications to all this:
1. In order to upgrade to seven-speed, you must re-space frame, through cold-setting (translation: bending it). If you don't have a steel frame, this is inadvisable, and you're really stuck with five speeds.
2. You will indeed need to re-dish the rear wheel, although not necessarily by 6mm. That has to do with a combination of the new OLD and difference in size between the five and seven-speed freewheels. In fact, I would hope that you don't have to re-dish by as much as 6mm - you are adding two cogs, sure, but the space between the cogs is also significantly reduced. I really have no idea, but I would hazard a guess that you won't need to change the dish by any more than 4mm or so.
This is, of course, assuming that your current hub and axle will fit a frame with 126mm spacing. It isn't guaranteed. It isn't necessary to buy a new hub, but if the axle is too short... good luck finding a replacement. You might just want to buy or build yourself a new rear wheel. Good luck with this project!
dooley
10-30-05, 06:44 PM
It's a 135mm bullseye hub in a 135mm frame, so hopefully all I'll have to do is move some washers around on the hub and re-dish the wheel slightly.
As it stands I have appx 4mm between the chain and the frame, it sounds like it will work just dandy.
As for the freewheel I was hoping to get it from Harris Cyclery, but I take it they've sold out?
As it stands I have appx 4mm between the chain and the frame, it sounds like it will work just dandy.
As for the freewheel I was hoping to get it from Harris Cyclery, but I take it they've sold out?
grolby
10-30-05, 08:27 PM
I have no idea. You'll have to check their website.
Anyhow, how is it that you have a five-speed freewheel on a 135mm hub!? Do you have a department store bike? I can't think of any quality bicycle that would combine 135mm spacing with a five speed freewheel. This is purely editorializing on my part, but I would suggest that tinkering with a bike like that is really a waste of your money, and not worth the time. I'm not blowing smoke here - I've been there, and it would have been much smarter to get out of the game $150 sooner. That much more cash available for the bike I replaced it with, which was 12 years older and 12 times better.
Unless, of course, it is just a decent-quality bicycle that happens to have a five-speed freewheel, in which case, go to it. Actually, in any case, if you want to work with it, go for it. It is your bike, after all :).
Anyhow, how is it that you have a five-speed freewheel on a 135mm hub!? Do you have a department store bike? I can't think of any quality bicycle that would combine 135mm spacing with a five speed freewheel. This is purely editorializing on my part, but I would suggest that tinkering with a bike like that is really a waste of your money, and not worth the time. I'm not blowing smoke here - I've been there, and it would have been much smarter to get out of the game $150 sooner. That much more cash available for the bike I replaced it with, which was 12 years older and 12 times better.
Unless, of course, it is just a decent-quality bicycle that happens to have a five-speed freewheel, in which case, go to it. Actually, in any case, if you want to work with it, go for it. It is your bike, after all :).
dooley
10-31-05, 03:19 AM
The bike was put together by me, it's not a store bought one. I used a 5sp so that I didn't have to dish the wheel much, because I hate dished wheels. As it happens I did dish the wheel slightly to sort out the chain line, so I figured I might as well take advantage of it and run a wider freewheel.
MichaelW
11-01-05, 04:52 AM
I switched from a 5spd to a 7 spd freewheel with no modicfications at all. No redishing, no respacing, just spin off the old on and on with the new.
The 7 speed has less clearance at the seatstay but enough for safe use.
The 7 speed has less clearance at the seatstay but enough for safe use.
BubbaDog
11-01-05, 10:21 AM
I switched from a 5spd to a 7 spd freewheel with no modicfications at all. No redishing, no respacing, just spin off the old on and on with the new.
The 7 speed has less clearance at the seatstay but enough for safe use.
What 5 speed freewheel did you have before, and what 7 speed did you put on?
B'Dog
The 7 speed has less clearance at the seatstay but enough for safe use.
What 5 speed freewheel did you have before, and what 7 speed did you put on?
B'Dog
MichaelW
11-01-05, 11:10 AM
They were both std Shimano freewheels, 12-28