Rear wheel, cassette freehub question

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2010-01-28 12:55 PM

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Subject: Rear wheel, cassette freehub question
Hi All.

This is a question I have been pondering and I hope some of the technical gurus out there can help.

I have an old road bike that this newbie uses for tris(bianche trefeo). During a training ride I hit a pothole (pulled the front over it but slammed the back into it) and now I have a flat spot on the rear. I would like to replace it with a newer rear wheel, but the wheel has a 7 speed "freehub". Is it possible to get a new wheel that will take a new 7 speed cassette? I assume that i will need spacers to position the cassette properly? The reason I  want to stay with 7 speed is because the bike is old and has suntour downtube index shifters and I am on a very tight budget. I would perfer not to have to upgrade the shifters or derailer.

these are the wheels I am thiinking about: http://www.pricepoint.com/detail/18454-365_MADF28-3-Parts-75-Wheelsets/Maddux-Aero-Racing-F20-Road-Wheelset-White.htm

thhis is the cassette:http://www.nashbar.com/bikes/Product_10053_10052_200421_-1_200300_200276_200429

Thank You in advance. I truly appriciate you time in answering this question

JD

2010-01-28 1:19 PM
in reply to: #2640345

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Master
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Subject: RE: Rear wheel, cassette freehub question
according to sheldon brown

In general, all Shimano Cassette Freehubs will work with all Shimano cassettes, any number of speeds. There are a very few exceptions:
  • 7-speed hubs won't normally accept 8-, 9- or 10 speed cassettes without modification. Click here for details.

    •  

  • 7-speed cassettes fit fine on 8- and 9-speed (and some 10-speed) hubs if you put a 4.5 mm spacer onto the body before the cassette. Click here for details.
This is the page
http://www.sheldonbrown.com/speeds.html

and here is even more info (the details listed above) http://www.sheldonbrown.com/k7.html
2010-01-28 2:47 PM
in reply to: #2640345

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Subject: RE: Rear wheel, cassette freehub question
I've got a 7-speed Trek that I used to use for tri's so I'm familiar with your hardware.

First, I'm pretty sure those wheels you linked to will not work.  Measure the distance between the drop-outs that the wheel axle fits in.  Most 7-speeds are 126-128mm (I think) where most modern bikes are quite a bit wider.  That means you'll have to bend your frame a bit to fit a 8/9/10-speed compatible hub and you do NOT want to do that.

I think your cheapest options are to either find an already built-up 7-speed rear wheel or take your wheel to your LBS and ask them to build up your freehub with a new rim.  Rims are pretty interchangeable assuming you can count spokes and there's nothing wrong with your freehub, right?

Time for a visit to your friendly LBS mechanic.
2010-01-28 3:07 PM
in reply to: #2640345


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Subject: RE: Rear wheel, cassette freehub question
I have a 7 speed trek with downtube shifters that sounds very similar to your bike.

I also replaced the wheels on mine as well, and here is what I did:

I would visit a local bike store, and purchase a used rear wheel, it will be much cheaper (I picked one that was $30, but they had a wide variety).

Here are the other things you will need, just so you aren't missing anything:

1: If hub is 8/9/10 speed, you will need the spacer (around $2), if it's 7 speed, you will not.
2: Rim tape for your new wheel (around $5)
3: Tire levers to remove your tire (around $4)

You will also need the bike shop to put remove the cassette and put it on the new wheel, unless you have the tools to do it yourself, they most likely will do this for free. I would change the tire and tube yourself so you get some practice.

Good luck!

2010-01-28 8:00 PM
in reply to: #2640345

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Subject: RE: Rear wheel, cassette freehub question
The OP does not have a cassette - he has a freewheel.  A cassette slips right onto the hub (modern) but a freewheel threads on (old-skool).

Definitely check your rear dropout spacing before doing anything.
2010-01-28 9:01 PM
in reply to: #2640726

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Subject: RE: Rear wheel, cassette freehub question
Tyrell - 2010-01-28 2:47 PM I've got a 7-speed Trek that I used to use for tri's so I'm familiar with your hardware.

First, I'm pretty sure those wheels you linked to will not work.  Measure the distance between the drop-outs that the wheel axle fits in.  Most 7-speeds are 126-128mm (I think) where most modern bikes are quite a bit wider.  That means you'll have to bend your frame a bit to fit a 8/9/10-speed compatible hub and you do NOT want to do that.

Indeed, you definitely want to check your rear spacing.  Most older, 6- and 7-speed road bikes from the 1980's have a rear spacing of 126mm.  The hub on the rims you are looking to buy are for a bike with rear spacing of 130mm. 

As Tyrell says, finding an old wheel will be your cheapest option.  Look on CL and search eBay for 'NOS' 126mm wheels. 

As for adjusting the rear spacing....you definitely CAN do it, but don't 'bend' it using a 2x4. Use a spreader to cold forge the spacing in an exact manner...or pay $20 for your LBS to do it. 

2010-01-29 11:18 AM
in reply to: #2640345

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Subject: RE: Rear wheel, cassette freehub question
I checked the spacing last night and it is 128mm.

The Hub is good, a bit loose but a rebuild will fix that.
I like the idea of the spreader.

Either way I think I will bring the wheel to the LBS and see what they have to say.

Thanks all.....
2010-01-29 11:53 AM
in reply to: #2640345

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Subject: RE: Rear wheel, cassette freehub question
On a steel frame, it is not an issue to spread the frame the couple mm to accept a newer wheel.

Surly builds the cross check with a 132.5mm spacing so you can pinch it down for 130mm road hubs or pull it apart to accept 135mm mountain hubs.

Getting the wheel rebuilt with a new rim and your current hub or getting an old wheel with the same style hub is going to be the best way to ensure that you do not have issued with using a new cassette with your old chain and chainrings.
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