TA Specialites Chainset - ISO or JIS?

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leighz
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TA Specialites Chainset - ISO or JIS?

Postby leighz » 1 Apr 2008, 11:38am

the arms are marked:

175 BSC G2 France

thirdcrank
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Postby thirdcrank » 1 Apr 2008, 12:18pm


leighz
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Postby leighz » 1 Apr 2008, 12:29pm

ta

so if they're currently on a 68-113 jis BB at the moment - do I need to buy a slightly longer axle iso BB to keep the chainline as it is?

thirdcrank
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Postby thirdcrank » 1 Apr 2008, 12:32pm

Sorry, if you are asking me, I don't know. If you look elsewhere on the SB site he explains chain line, how to calculate it, and he was part way through a project to catalogue everything on the subject of bottom brackets.

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gaz
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Postby gaz » 1 Apr 2008, 1:59pm

The TA site gives chainline info for various of it's modern bb and crank combinations (Click on more product info). Interestingly it doen't say whether they are JIS or ISO.

Frankly 4-5mm on the bb axle only seems to produce 1.5mm difference on chain line according to TA's tables. Don't ask me why? :oops:

I would think that the primary consideration is not scraping the chainstay with the inner ring.

TC's above link to SB seems the best spot. It even gives info on mix and matching JIS and ISO components.
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Paul Smith SRCC
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Re: TA Specialites Chainset - ISO or JIS?

Postby Paul Smith SRCC » 1 Apr 2008, 3:36pm

TA Carmina and all the current TA chainsets use a JIS bb.

Therefore some use the Shimano 'JIS' taper bb with these chain sets. JIS I believe stands for 'Japanese Industry Standard' and used not only by Shimano but many of the other Asian Manufacturers, as apposed to the 'ISO' size, that is the size that most of the European manufacturers use as standard like Campagnolo for example, although they look similar they are very slightly different

It is not about chain line though, although both use the same two degree taper, the main difference is in the actual length of the taper, the JIS version is slightly longer, so if you try and put a crank designed for a JIS BB onto an ISO shorter tapered BB (like a Shimano Chainset onto a Campagnolo BB), then the crank depth may go to far up the crank and actually reach the end of the taper.

Not such a problem vice versa of course as in your case with a Campagnolo Chainset onto a Shimano bb as the crank depth will not reach the end of the taper; still not to be recommended though, especially when bottom brackets are relatively inexpensive. Which model Chainset is it, the Campagnolo site will advise what bb width is required.

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leighz
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Postby leighz » 1 Apr 2008, 9:35pm

paul - you've confused me! Sheldon says it's ISO ...you say JIS?!?

not sure which model it is - I bought 2nd hand off here - running 8spd double at the moment. So it's not a recent version.

Just want to avoid crank cracking due to incorrect fitting of BB which I understand can be a problem.

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Paul Smith SRCC
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Postby Paul Smith SRCC » 1 Apr 2008, 9:53pm

We could be both right, Sheldon Brown has not specified which model of TA chainset(s), where as I have with "Carmina and all the current".

The older models may well have been ISO, although most Cyclo Touriste chainsets would be fitted with their own TA bb so it was a question I was never asked and as such I am not sure what they were, although likely that Sheldon Brown is correct and that he is referring to models that have been replaced, with those that are JIS and not ISO. You could try contacting the UK distributor Chicken Cycles for clarification on what you need for yours, their number is 01582 873 329, ask for 'Mike', he has been their a long time and will be aware of any changes, you will need to know which model you have though. The link to Chicken Cycles has all the current models shown, some older models are:

Zephyr
Alize
Cyclotouriste

Now that they are JIS it does mean you can use a Shimano BB which are more readily available than ISO. TA may have done that for this reason, although in a way it does encourage people not to use their own TA BB so they potentially lose a sale in that respect.

Paul_Smith
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leighz wrote:paul - you've confused me! Sheldon says it's ISO ...you say JIS?!?

not sure which model it is - I bought 2nd hand off here - running 8spd double at the moment. So it's not a recent version.

Just want to avoid crank cracking due to incorrect fitting of BB which I understand can be a problem.
Last edited by Paul Smith SRCC on 2 Apr 2008, 10:01am, edited 3 times in total.

leighz
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Postby leighz » 1 Apr 2008, 10:20pm

ta - will give chicken cycles a bell

leighz
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Postby leighz » 2 Apr 2008, 11:00am

some poor and unflattering photos here if anyone can identify them?

Image

Image[/url]

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Paul Smith SRCC
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Postby Paul Smith SRCC » 2 Apr 2008, 12:05pm

looks like a TA Alize, Mike from Chicken Cycles as I mentioned earlier should know as they were the UK supplier for TA back then as they still are now, number again is 01582 873 329.

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gaz
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Postby gaz » 3 Apr 2008, 9:35am

Looks more like a Zephyr to me. Some pics here. The Zephyr uses the crank arm as part of the spider.

The same sight has info for appropriate TA bottom brackets but again fails to say if they are ISO or JIS. The page does list Phil Wood BB lengths in JIS for the TA Carmina chainset.

My own Zephyr is mounted on a Shimano cartridge BB which I would presume to be JIS.
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Paul Smith SRCC
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Postby Paul Smith SRCC » 3 Apr 2008, 9:59am

Could well be Zephyr, essentially a similar looking chainset with different size spider, Alize BCD I believe was 130mm and Zephyr had a BCD of 110mm

I telephoned Mike at Chicken Cycles this morning who informed me that Alize and Zephyr were the first that changed from ISO to JIS

Paul Smith
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gaz wrote:Looks more like a Zephyr to me. Some pics here. The Zephyr uses the crank arm as part of the spider.

The same sight has info for appropriate TA bottom brackets but again fails to say if they are ISO or JIS. The page does list Phil Wood BB lengths in JIS for the TA Carmina chainset.

My own Zephyr is mounted on a Shimano cartridge BB which I would presume to be JIS.

leighz
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Postby leighz » 3 Apr 2008, 3:48pm

chicken said: 'All TA cranks have always been JIS except from a cyclotourist model' and that I'd need a 122mm length

TA said: 'I think your pair of cranks is Alize. Anyway, for the two cases, you would need a ISO bottom bracket'

and Peter White said: 'Look pretty badly beaten up. I sure wouldn't ride them. I've seen what happens to riders when a crank breaks. It isn't pretty' and suggested JIS.

...should see my mtb cranks.

?!?

None the wiser.

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Paul Smith SRCC
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Postby Paul Smith SRCC » 3 Apr 2008, 3:54pm

I don't recall any models between cyclotouriste and Alize/Zephr anyway so 'All TA cranks have always been JIS except from a cyclotourist model' amounts to the same as what I stated above.

What reason TA give for then contradicting their long standing UK supplier by stating "you would need a ISO bottom bracket'?

They do look a but beaten up though, I have broken a few cranks in my time, not pleasant when that happens.

In conclusion we are as you say none the wiser, I assume you contacted TA via their site, so they should be correct, depends who answered the email of course, for all we know it could easily have been a new person, so then again are they correct or not :roll:?

After reading all this contradictory information I phoned Chicken Cycles again as I wanted to know, unfortunately all their data to verify was lost in when their warehouse burned to the ground last year, but Gary, like Mike who I spoke to earlier has worked their for years, including when Alize/Zephr models were current and and he told me this much, that the BB they used with them were JIS!

Paul Smith
www.bikeplus.co.uk



leighz wrote:chicken said: 'All TA cranks have always been JIS except from a cyclotourist model' and that I'd need a 122mm length

TA said: 'I think your pair of cranks is Alize. Anyway, for the two cases, you would need a ISO bottom bracket'

and Peter White said: 'Look pretty badly beaten up. I sure wouldn't ride them. I've seen what happens to riders when a crank breaks. It isn't pretty' and suggested JIS.

...should see my mtb cranks.

?!?

None the wiser.
Last edited by Paul Smith SRCC on 3 Apr 2008, 4:54pm, edited 4 times in total.