Spa Cycles XD-2 touring cranks bottom bracket size

[alicat]

Hi all

I am changing the cranks on my Longstaff from TA Specialites to Spa Cycles XD-2 touring cranks that have the mark XD2R on them and look to be a copy or unbranded version of these Sugino cranks. The bike is a steel triple chainset 130mm rear dropout audax/tourer with 26" wheels. The outer and middle rings are TA Zephyr and the inner ring is TA Zelito.

I fitted a Shimano UN54 bottom bracket in the 110mm length recommended by Spa but the inner chainring bolts are rubbing on the chainstay. I note Sugino recommend a 113mm bb for a triple and so do Rivendell.

I fitted the new cranks to the original 130mm bottom bracket and the chainline needs to come in by about 8.5mm to achieve a chainline of 47.5mm. I have relied on this Harris Cyclery measurement of the driveside length of bottom brackets, which suggests a bb length between 113mm and 115mm.

The distance between the chainring bolt and the stay during this experiment is about 8mm, which indicates 115mm could be tight.

There is a 4mm spacer stack between the inner and middle chainrings - what is it there for? Could I remove it and fit shorter bolts?

Thoughts? Workarounds?

I don't want to start a collection of nearly new bottom brackets if possible.

Thanks

 

[RecordAceFromNew]

I don't want to start a collection of nearly new bottom brackets if possible.

Amen to that!

It has to be unusual, and I am surprised, that what spa / Sugino provide is incorrect. OTOH I am not sure if I would rely on the Harris info for chainline calculation - e.g. I believe Shimano's 113mm and 115mm bb's deliver the same chainline.

For traditional road triples, chainline is 45mm, and if that is delivered by a 110mm bb as spa might be indicating then it is consistent with Sugino's specification that a 113mm (and indeed 115mm) bb would deliver very close to 47.5mm (e.g. for a mtb application). Incidentally there is front mech compatibility implication if you push chainline too much.

While you are getting chainstay clash with the 110mm, could you guesstimate what chainline, even if approximate, that is delivering? I would be surprised if it is not 45mm, and am wondering if you have exceptionally splayed chainstays near the bb.

Regarding your 130mm bb spindle, its length seems unusual to me - does it have any marking in relation to e.g. those here.

Fyi the rear chainline (at the middle of the cluster) for a 130mm OLND hub should be very close to 43mm. There is however no reason to try to achieve that up front for a derailleur system.

With respect to your question regarding spacers, what are the spacings between the rings?

 

[alicat]

Thanks for the info, RecordAce. I was hoping you would be along.

The approx chainline with the 110mm bottom bracket is indeed c45cm. I think the problem is the spacers between the middle and inner rings. They are pushing the inner ring out by an extra 6-7mm (not 4mm as I thought originally) and making the inner ring foul the chain stay. The chainstays aren't splayed.

The 130mm bb is a Shimano UN-72 from about 1999.

I think I will remove the spacers and get some shorter bolts and see if anything is fouled using the 110mm bb.

 

[RecordAceFromNew]

Thanks for the info, RecordAce. I was hoping you would be along.

The approx chainline with the 110mm bottom bracket is indeed c45cm. I think the problem is the spacers between the middle and inner rings. They are pushing the inner ring out by an extra 6-7mm (not 4mm as I thought originally) and making the inner ring foul the chain stay. The chainstays aren't splayed.

The 130mm bb is a Shimano UN-72 from about 1999.

I think I will remove the spacers and get some shorter bolts and see if anything is fouled using the 110mm bb.

Spacing between the chainrings should be no more than 5mm. Something is wrong with the chainset otherwise.

I think the longest UN7x spindles were 127.5mm (with code EL). delivering 8mm additional chainline compared to 113mm/115mm.

 

[RecordAceFromNew]

Actually this may be useful to you:

"TA ring with a Sugino crank, the inner ring on a triple ends up spaced further from the middle ring than it should." from Peter White.

 

[alicat]

Ah, it's all clear now. Peter White says:

Sugino doesn't use loose spacers for mounting the inner triple rings on all of their cranks. They often have the inner ring mounted to a stud that's a part of the forged crank itself.​

​

On close examination of the two cranks, the Sugino one does has the stud mentioned so I can remove the spacers and have another go.

By the way, I've remeasured the existing spindle and it could be 127.5mm - time to invest in a calliper, me thinks.

Thanks so much for putting me back on the right track.

 

[rualexander]

I've used the Spa cranks and also the same(?) cranks branded as Stronglight, I haven't seen or used any spacers anywhere on them, just normal chainring bolts.

 

[alicat]

Well, I've removed the spacers and the chainline looks good with the 110mm bb. When the rebuild is finished I will check if the TA rings cause an issue

"TA ring with a Sugino crank, the inner ring on a triple ends up spaced further from the middle ring than it should." from Peter White.

Rualexender - what rings did you use with the cranks?