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Swapping freehubs

Old 11-15-16, 06:34 PM
  #1  
linberl
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Swapping freehubs

Here's what is probably a dumb question to some of you...I need to replace my freehub body or get a new wheel. While I am having a very hard time finding a replacement (Sunrace, 135mm, 7 speed) I am wondering if one can put a freehub body for 8 or more gears onto the existing sunrace hub? I'd like to have more gears and if that works, I don't need a new wheel (assuming I can find the part). And, yes , it uses a HG50 cassette, not a freewheel.
I found something that looks correct at Niagara Bicycles but haven't ridden over to my lbs to check that it is what I need yet - it's the whole hub but I could just salvage the freehub body from it (under $25 for the whole thing) which cuts the labor way down.
Niagara has a 7 speed version and an 8 speed version - can I use the 8?

If it matters here's the parts:
Sunrace Rear Hub, Hbm53, 36x135, 7-Speed Cassette, Quick-Release, Silver

You Pay:
$24.28

Rating:


SKU:
453635

Brand:
SunRace

Availability:

  • In stock for shipping, 4-5 days
  • Available for in-store pickup in 4-5 days
Current Stock:
2




Product Description

  • 6061 aluminum
  • Loose ball bearings
  • RR
  • 7s Cass Shi
  • 36H


QR 135mm, Alloy, Sil, 440g

OR >>>>>>>
Sunrace Rear Hub, Hbm53, 36x135, 8-Speed Cassette, Quick-Release, Silver

You Pay:
$24.28

SKU:
453636

Brand:
SunRace

Availability:

  • In stock for shipping, 4-5 days
  • Available for in-store pickup in 4-5 days
Current Stock:
4


Product Description

  • 6061 aluminum
  • Loose ball bearings
  • RR
  • 8s Cass
  • 36H


QR 135mm, Alloy, Sil, 440g
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Old 11-15-16, 06:52 PM
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Very difficult to know wether it will fit on the old hub.
But even if it does fit you will most likely have to resapce the axle and redish the wheel.
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Old 11-15-16, 06:55 PM
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7-speed and 8-speed cassettes have spacing between the cogs that is almost identical. Consequently the 8-speed freehub body has to be wider than 7-speed. Things to check:

1. Dropout spacing. 8-speed and above dropouts are usually 130 mm or 135 mm. Bikes with 7-speed dropouts are 126 mm or 130 mm. If your bike has 130 mm dropouts, you have cleared the first hurdle.

2. Freehub body. Shimano freehub bodies, while not identical, are close enough that I've successfully replaced several 7-speed freehub bodies with 8-speed ones. Sunrace, I'm less confident, but it might work.

3. The other stuff. Everything on a bicycle works together. If you have index shifting and you want to keep it, you'll have to replace the shifters. 7 & 8-speed chains are the same, lucky for you.

Bottom line. After you have done all this, what have you gained? You can get the same gear range using a 7-speed cassette so all you've gained is slightly smaller steps between gears. If it was my bike, I'd leave it 7-speed. In fact, my beater bike has a 7-speed cassette.
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Old 11-15-16, 07:15 PM
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Originally Posted by Retro Grouch View Post
7-speed and 8-speed cassettes have spacing between the cogs that is almost identical. Consequently the 8-speed freehub body has to be wider than 7-speed. Things to check:

1. Dropout spacing. 8-speed and above dropouts are usually 130 mm or 135 mm. Bikes with 7-speed dropouts are 126 mm or 130 mm. If your bike has 130 mm dropouts, you have cleared the first hurdle.

2. Freehub body. Shimano freehub bodies, while not identical, are close enough that I've successfully replaced several 7-speed freehub bodies with 8-speed ones. Sunrace, I'm less confident, but it might work.

3. The other stuff. Everything on a bicycle works together. If you have index shifting and you want to keep it, you'll have to replace the shifters. 7 & 8-speed chains are the same, lucky for you.

Bottom line. After you have done all this, what have you gained? You can get the same gear range using a 7-speed cassette so all you've gained is slightly smaller steps between gears. If it was my bike, I'd leave it 7-speed. In fact, my beater bike has a 7-speed cassette.
The bike is 135mm OLD. And yes, you make sense about leaving it a 7 speed. What I was hoping was to eventually turn it into a 1x10, since I know 10 speed cassettes can go on 8 speed hubs. But if I would have to redish it, etc., then it's not worth it to me. I'll see if the 7 speed body can replace mine. If not, I guess it's a new wheel. I do have the option of adding a FD and getting 14 speeds but I love the simplicity of a single chainring.
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Old 11-15-16, 11:45 PM
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1x is not about simplicity, 3x7 is. 1x is hype in my honest opinion.

7 speed freehub, on a 135 OLD wheel has better spoke angle, less dishing to one side, to accommodate wider freehub, so a bit stronger wheel. 7 speed chains and cassettes are cheap. They offer same gearing spacing as most 8 speed cassettes (7 speed ones are often found with identical teeth counts, just without the smallest sprocket). 10 speed will give you a few more in between gears, but usually on a slower end of the cassette, where it rarely matters.

If going for the 8+speeds, note that road 11 speed cassettes will not fit 8 speed freehub - they need even wider one.

With 135 OLD rear frame spacing, you could get a Shimano Deore rear hub, DT Swiss spokes and any decent double walled aluminium rim - building a brand new wheel. If using the old one, it will have to be re-dished.

Shifters - if they are friction shifters, over 8 speeds will be hard to use with them. If indexed, more speeds will require new shifters.
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Old 11-16-16, 05:10 PM
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Originally Posted by Slaninar View Post
1x is not about simplicity, 3x7 is. 1x is hype in my honest opinion.

7 speed freehub, on a 135 OLD wheel has better spoke angle, less dishing to one side, to accommodate wider freehub, so a bit stronger wheel. 7 speed chains and cassettes are cheap. They offer same gearing spacing as most 8 speed cassettes (7 speed ones are often found with identical teeth counts, just without the smallest sprocket). 10 speed will give you a few more in between gears, but usually on a slower end of the cassette, where it rarely matters.

If going for the 8+speeds, note that road 11 speed cassettes will not fit 8 speed freehub - they need even wider one.

With 135 OLD rear frame spacing, you could get a Shimano Deore rear hub, DT Swiss spokes and any decent double walled aluminium rim - building a brand new wheel. If using the old one, it will have to be re-dished.

Shifters - if they are friction shifters, over 8 speeds will be hard to use with them. If indexed, more speeds will require new shifters.
I live in the slower end of the cassette, lol, I'm 66 years old and there are lots of hills where i live. So for me, going to a 1x10 would basically mean adding some granny gears without loping off the faster gears to accomplish that. Right now I ride 13-30t, rarely using the 13 and often wishing for a bigger cog, but I would like to recover my 11t and add a 32 and/or 34. Not having a front der makes adjustments easier and simpler for me; ymmv. My shifter is an SRAM gripshift which I know I would need to replace.
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Old 11-16-16, 05:47 PM
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I have no Idea if sun race is compatible with anything but itself.. could be shimano compatible
that makes Business sense , other parts adopted Shimano Standards ..

The Sun Race group of companies now include sturmey archer ..

In My Dotage [69] I'm back To internal gear Hubs , because they shift at any speed, including stopped

so you may consider a hybrid 3 speed + Casette hub,( or just get a wheel with a shimano 8 speed Hub in it..)

Aside: If you look or have your favorite Bike shop do so there are casettes with a 14t High gear for Jr Racing..



Mechanically, the cassette lockring stays secure because it engages serrations on the top gear cog..So you have to use it,

but can set the Hi Limit screw to never shift the chain onto It. so it just fills the space & you have 7 of 8 gears to Use .


Maybe your current shifter will work , I have not pre tested that combo in advance.





'/,

Last edited by fietsbob; 11-16-16 at 05:53 PM.
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Old 11-16-16, 08:26 PM
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8 speed bodies can use 7 speed cassettes with the addition of a 4.5mm spacer.

https://www.amazon.com/Wheels-Manufa.../dp/B001CJVLWO

Later, if you want to go 8-10 speed, just get the cassette, chain & R. Shifter.
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Old 11-16-16, 11:08 PM
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Originally Posted by Bill Kapaun View Post
8 speed bodies can use 7 speed cassettes with the addition of a 4.5mm spacer.

https://www.amazon.com/Wheels-Manufa.../dp/B001CJVLWO

Later, if you want to go 8-10 speed, just get the cassette, chain & R. Shifter.
My chain will actually work for up to 9 speeds =). I'll need a new shifter. I just put a new cassette on so I will wait til it needs replacing to change everything. Yes, the idea is to use the spacer behind the 7 speed for the short term.

But - I may actually have found a replacement for my sunrace hub for $25 that I can just take the freehub body off of...which would not require any major wheel work for now. If it turns out it is the right one, that's what I'll do for the short term. It's an inexpensive solution which will carry me til I feed more financially willing to pop for a new wheel/cassette/shifter. The local Bike Friday/folding bike shop is looking into it for me.

Of course, if it is not compatible, then I'm going with a replacement wheel. The question at that point becomes do I buy something cheap and serviceable or shell out for something higher quality than what I have now. Depends on the the stock market and my bonds, lol.
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Old 11-16-16, 11:45 PM
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Have you checked to make sure you don't already have the 8 speed free Hub with a spacer?
It might help one avoid feeling dumb IF that's the case.
Some bikes came that way.
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Old 11-17-16, 03:10 AM
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Originally Posted by linberl View Post
I live in the slower end of the cassette, lol, I'm 66 years old and there are lots of hills where i live. So for me, going to a 1x10 would basically mean adding some granny gears without loping off the faster gears to accomplish that. Right now I ride 13-30t, rarely using the 13 and often wishing for a bigger cog, but I would like to recover my 11t and add a 32 and/or 34. Not having a front der makes adjustments easier and simpler for me; ymmv. My shifter is an SRAM gripshift which I know I would need to replace.
This can hardly be the case with a (fitness appropriate) 42-32-22 triple crankset.
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Old 11-17-16, 10:27 AM
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Originally Posted by Bill Kapaun View Post
Have you checked to make sure you don't already have the 8 speed free Hub with a spacer?
It might help one avoid feeling dumb IF that's the case.
Some bikes came that way.
No such luck :-(
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Old 11-17-16, 10:28 AM
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Originally Posted by Slaninar View Post
This can hardly be the case with a (fitness appropriate) 42-32-22 triple crankset.
I don't want a front derailleur.
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Old 11-17-16, 10:47 AM
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FH CASS SUNRACE CSM40 11-34 UCP 7s or go smaller front ring?
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Old 11-17-16, 12:01 PM
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Originally Posted by curbtender View Post
FH CASS SUNRACE CSM40 11-34 UCP 7s or go smaller front ring?
I had an 11-30 originally and the jumps between gears were too far for me. That's a big part of why I want to go up to a 10 speed, to make the jumps between gears less harsh. My knees will be lots happier. I could live without getting the 11t back but jumping from 29 to 34 is a lot. My perfect gear range would be 11-13-15-17-19-21-24-27-30-32.
Maximum 3 tooth difference. I know I can put something like that together if I can't find it already configured, just need to sort my wheel out first.
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Old 11-17-16, 10:36 PM
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Originally Posted by linberl View Post
I had an 11-30 originally and the jumps between gears were too far for me. That's a big part of why I want to go up to a 10 speed, to make the jumps between gears less harsh. My knees will be lots happier. I could live without getting the 11t back but jumping from 29 to 34 is a lot. My perfect gear range would be 11-13-15-17-19-21-24-27-30-32.
Maximum 3 tooth difference. I know I can put something like that together if I can't find it already configured, just need to sort my wheel out first.
If you have problems with a 5 tooth jump from the 2nd slowest, to the slowest gear ratio, I'd guess your front chainring is too big. Though, with a 1x, maybe it has to be that way, to have a decent top end speed for flats, but if Front x 11 rear isn't the ratio you spin out on flats regularly, consider getting a smaller front chainring.
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Old 11-18-16, 10:24 AM
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Originally Posted by Slaninar View Post
If you have problems with a 5 tooth jump from the 2nd slowest, to the slowest gear ratio, I'd guess your front chainring is too big. Though, with a 1x, maybe it has to be that way, to have a decent top end speed for flats, but if Front x 11 rear isn't the ratio you spin out on flats regularly, consider getting a smaller front chainring.
I dropped my chainring down to a 50t (this is a 20" folding bike). If I go any lower, I will definitely not have the gearing I need for flats. Right now, the 30t is not sufficient for climbing the bigger hills around me; I know I need a 32 or 34, probably 34. It's all about finding the balancing act between the maximum range and the incremental jumps. Bigger jumps cause problems for one of my knees, which is shot. Thanks for all your advice, though.
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Old 11-18-16, 10:30 AM
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Originally Posted by linberl View Post
I dropped my chainring down to a 50t (this is a 20" folding bike). If I go any lower, I will definitely not have the gearing I need for flats. Right now, the 30t is not sufficient for climbing the bigger hills around me; I know I need a 32 or 34, probably 34. It's all about finding the balancing act between the maximum range and the incremental jumps. Bigger jumps cause problems for one of my knees, which is shot. Thanks for all your advice, though.
I don't like big jumps in faster end of the cassette, but on the "climbing" end (biggest 3 sprockets) I even prefer the jumps to be greater.

When climbing, I do one shift at the rear and get a much easier gearing - no need to shift two, or three times, loosing pressure on the pedals each time.

When I reach the top, goes the other way round: one shift gets me going substantially faster.
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