Suntour cranks to 10x2 speed upgrade?

Feathered
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Suntour cranks to 10x2 speed upgrade?

Postby Feathered » Mon Dec 04, 2023 9:18 pm

Hi, have come across a Shimano rear rim with 11-25 10 speed cassette at good price and got a few ideas rolling around to upgrade a bike from 6 speed, I could be wrong but I'm currently running a Suntour Cyclone crank set which I purchased new and sentimental to, from information would I need to change the inner ring to a 10 speed spec in order for it to pick up the new thinner chain? If so is there anything available today to fit that Suntour bolt pattern? Not sure if they interchange with Shimano?
Thanks to any answers 👍

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Duck!
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Re: Suntour cranks to 10x2 speed upgrade?

Postby Duck! » Mon Dec 04, 2023 9:57 pm

There is very little difference in inner width between 6 & 10-sp. chain. 10-sp. is narrower, but there is most likely enough tolerance in the chainring thickness for it to fit fine.

What you will probably find though is that the frame's rear dropouts are spaced to 126mm, where the newer wheel you have will be 130mm, which will make fitting it to the frame a bit tricky. It is possible with steel frames to "cold set" the stays a bit wider, but you need to ensure you're bending each side equally so the wheel stays centred and aligned with the frame axis. Cold setting is not recommended for aluminium frames, as the process can weaken the material, leading to cracking.
I had a thought, but it got run over as it crossed my mind.

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P!N20
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Re: Suntour cranks to 10x2 speed upgrade?

Postby P!N20 » Tue Dec 05, 2023 7:11 am

Feathered wrote:
Mon Dec 04, 2023 9:18 pm
is there anything available today to fit that Suntour bolt pattern?
Unlikely, the Suntour Cyclone BCD is 144mm which didn’t survive past the 80’s…with the exception of track chainrings which don’t work with road chains.

Feathered
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Re: Suntour cranks to 10x2 speed upgrade?

Postby Feathered » Tue Dec 05, 2023 11:57 am

Yes rear spacing is 126 but wheel is popping in with almost no effort for now and wheel dead straight, will open it at a later date as still a non running project, will have a go with the 10speed chain, all else fails try something else
Duck! wrote:
Mon Dec 04, 2023 9:57 pm
There is very little difference in inner width between 6 & 10-sp. chain. 10-sp. is narrower, but there is most likely enough tolerance in the chainring thickness for it to fit fine.

What you will probably find though is that the frame's rear dropouts are spaced to 126mm, where the newer wheel you have will be 130mm, which will make fitting it to the frame a bit tricky. It is possible with steel frames to "cold set" the stays a bit wider, but you need to ensure you're bending each side equally so the wheel stays centred and aligned with the frame axis. Cold setting is not recommended for aluminium frames, as the process can weaken the material, leading to cracking.

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elantra
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Re: Suntour cranks to 10x2 speed upgrade?

Postby elantra » Wed Dec 06, 2023 1:49 pm

Feathered wrote:
Tue Dec 05, 2023 11:57 am
Yes rear spacing is 126 but wheel is popping in with almost no effort for now and wheel dead straight, will open it at a later date as still a non running project, will have a go with the 10speed chain, all else fails try something else
Duck! wrote:
Mon Dec 04, 2023 9:57 pm
There is very little difference in inner width between 6 & 10-sp. chain. 10-sp. is narrower, but there is most likely enough tolerance in the chainring thickness for it to fit fine.

What you will probably find though is that the frame's rear dropouts are spaced to 126mm, where the newer wheel you have will be 130mm, which will make fitting it to the frame a bit tricky. It is possible with steel frames to "cold set" the stays a bit wider, but you need to ensure you're bending each side equally so the wheel stays centred and aligned with the frame axis. Cold setting is not recommended for aluminium frames, as the process can weaken the material, leading to cracking.
I had a 1987 frame (Repco Vertex, lightweight Reynolds 531 tubing) which in the course of its lifespan probably did about 90,000 km.
Of course being 1987 era it was 126 mm between the rear wheel stays (dropouts)

But towards end of its lifespan it would ONLY work properly with 9/10 speed wheels- 130 mm spacing
Presumably in the course of 30 odd years it did so many miles and so many wheel changes that the stays were subtly spread apart.

I have another slightly older frame (1983 Miyata) which although made from slightly beefier thickness tubing is now much the same - will now only work with 9/10 speed wheels.

Oh and the 1987 bike came stock standard with a Suntour Cyclone Crankset that in fact was the more modern 130mm bcd standard. (Not 144mm bcd)
I don’t doubt that at some earlier stage in the 1980’s the “Cyclone” cranksets were 144 mm bcd, but a significant change must have occurred presumably before 1987.

Good luck with your renovation.

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P!N20
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Re: Suntour cranks to 10x2 speed upgrade?

Postby P!N20 » Wed Dec 06, 2023 3:53 pm

elantra wrote:
Wed Dec 06, 2023 1:49 pm
Oh and the 1987 bike came stock standard with a Suntour Cyclone Crankset that in fact was the more modern 130mm bcd standard. (Not 144mm bcd)
I don’t doubt that at some earlier stage in the 1980’s the “Cyclone” cranksets were 144 mm bcd, but a significant change must have occurred presumably before 1987.

True, the 1987 catalogue has the Cyclone '7000' crankset as 130BCD: https://www.disraeligears.co.uk/site/su ... an_24.html

That one hasn't made it onto VeloBase.

Feathered
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Re: Suntour cranks to 10x2 speed upgrade?

Postby Feathered » Wed Dec 13, 2023 10:22 pm

I'll check that tomorrow night with the crank size out of curiosity, I remember buying them in 86-87, have now ordered a matching new rear wheel and mint Dura Ace 7420 derailler set for this build, new Shimano 8 speed indexed down tube levers which I'll only run front derailleur in index and rear in friction, already have the 600ax head stem and Tange Areo headset which I purchased new in 87. Thanks for replying .

P!N20 wrote:
Wed Dec 06, 2023 3:53 pm
elantra wrote:
Wed Dec 06, 2023 1:49 pm
Oh and the 1987 bike came stock standard with a Suntour Cyclone Crankset that in fact was the more modern 130mm bcd standard. (Not 144mm bcd)
I don’t doubt that at some earlier stage in the 1980’s the “Cyclone” cranksets were 144 mm bcd, but a significant change must have occurred presumably before 1987.

True, the 1987 catalogue has the Cyclone '7000' crankset as 130BCD: https://www.disraeligears.co.uk/site/su ... an_24.html

That one hasn't made it onto VeloBase.

Feathered
Posts: 6
Joined: Mon Oct 30, 2023 8:08 pm

Re: Suntour cranks to 10x2 speed upgrade?

Postby Feathered » Fri Dec 15, 2023 1:16 pm

Yep Suntour Cyclone 7000, 130 BCD

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