Change of chainset

[painter]

At present I have a full 105triple group set on my bike 50 39 30. 11 28 On rear. I wish to change the chainset to a. Spaxd2 touring triple 48 38 28 wouldI only have to change the bottom bracket or would I face other problems I would be very grateful for any advice thanking you painter

[Freddie]

Are you changing it because the rings are worn out? Because the gear ratios will be practically the same.

[iandriver]

I've done exactly this on a 9 speed Tiagra (chainset) Sora mix triple groupset, but I swapped out the inner ring for a 26 on the Spa (the 28 went on the old Tiagra which is now on my CX bike BTW, so no reason not to swap out just the inner ring on the 105 to a 28 if that helps as far as I can see, 12-30 on the rear of mine (later Sora rear mech))

[painter]

Sorry my mistake I wish to change to a 48 36 26 regards painter

[TrevA]

It depends. Presumably your old chainset is a square taper type. If it is, then you might get away with just changing the chainset. New bottom brackets are less than £20 anyway - go for a Shimano UN55 in the width recommended by Spa on their website. The Shimano one will last much longer than a Stronglight one. You might have to move your front mech done a bit, to maintain a smooth change. I swapped a 50/39/30 hollow tech II triple for a Spa square taper 48/38/28. I got sick of replacing the bearings on the Hollowtech every 2-3000 miles. Shimano square taper BB has done 10000 miles so far with no problems - Stronglight one lasted less than a year (about 3000 miles).

[painter]

Hi treva that's what I thought .iwas just wanting reassurances thanks for you help.

[Brucey]

the last 105 triple to use a square taper BB was the 1057 model which used a 118mm length BB. All later 105 triples used various splined BB types.

Since the XD2 uses a shorter ST BB than even the 1057 then you would need a different BB anyway. Most 'road triples' use a 45mm chainline and a front mech that works with your old chainrings ought to work with the proposed new ones (provided you can move it down a few mm) so it ought to be reasonably straightforward to fit an XD2 and a matching BB.

FWIW if you can make/find a custom cassette 12-32 or 13-32 you might find that your extant chainset will give you similar gears to those you will get by changing the chainset as you propose. This setup will be slightly heavier but also slightly more efficient.

BTW not all recent shimano road triples use a 74mm BDC inner ring fitment; some of them (annoyingly) won't allow you to fit anything smaller than a 30T inside chainring.

cheers

[painter]

brucey. Thanks for your help. Painter.

[PJ520]

It depends. Presumably your old chainset is a square taper type. If it is, then you might get away with just changing the chainset. New bottom brackets are less than £20 anyway - go for a Shimano UN55 in the width recommended by Spa on their website. The Shimano one will last much longer than a Stronglight one. You might have to move your front mech done a bit, to maintain a smooth change. I swapped a 50/39/30 hollow tech II triple for a Spa square taper 48/38/28. I got sick of replacing the bearings on the Hollowtech every 2-3000 miles. Shimano square taper BB has done 10000 miles so far with no problems - Stronglight one lasted less than a year (about 3000 miles).

This is bad news for me as I've just been talked into installing a 105 Hollowtech triple, the square taper BB that came with the bike had 51,000 miles on before it started to wobble it but it looks like I'm going to get nowhere close to that out of the new stuff. FWIW I'm using 50-39-24 with 11-32 at the back. The 105 front shifting is silky smooth but it looks like bearing changes are in my near(ish) future. My LBS told me that square taper cranks are no longer available. Is that correct? If the Hollowtechs last as short as people say I want to go back to the old stuff. The reason I changed the cranks was paranoia about crank breakage after so many miles.

[Brucey]

.... I swapped a 50/39/30 hollow tech II triple for a Spa square taper 48/38/28. I got sick of replacing the bearings on the Hollowtech every 2-3000 miles....

This is bad news for me as I've just been talked into installing a 105 Hollowtech triple, the square taper BB that came with the bike had 51,000 miles on before it started to wobble it but it looks like I'm going to get nowhere close to that out of the new stuff..... My LBS told me that square taper cranks are no longer available. Is that correct? .....

ST cranks are still available in good quality cranksets, just not from shimano; they have relegated this 'inferior old technology' to their least expensive equipment. At least they still make half-decent bottom brackets. Sugino, Stronglight (amongst others) make good quality ST stuff, as do Velo Orange and compass cycles too. Best value (in the UK) are probably those supplied by Spa Cycles.

So I reckon you have three options for longer life;

1) try to make the hollowtech stuff last; I think that with the right approach (interior seals out, void filled with semi-fluid grease) the bearings ought to last a lot longer. Whether it is 'long enough' though, remains to be seen. A Hope BB is also a good approach (although it is not an inexpensive part).
2) get a new ST setup
3) Have your old cranks dye-penetrant inspected; if they are not cracked then they should have a few years left in them yet.

hth

cheers

[freeflow]

An alternative approach is to replace the 105 chainset with a Deore chainset. I've been using an XT (44/32/22) chainset with ultegra sti and front mech for the last 18 months.

[Brucey]

An alternative approach is to replace the 105 chainset with a Deore chainset. I've been using an XT (44/32/22) chainset with ultegra sti and front mech for the last 18 months.

which model XT and what chainline? I'd have expect some kind of front mech issue with that TBH...?

BTW some folk (myself included) are predisposed to avoid MTB chainsets on a touring bike because they mostly have an excessive 'Q' value vs ones that have a road bike origin.

I went as far as building up a triple chainset which is less than 140mm wide (across the pedal mountings) and I much prefer pedalling that to others, (even though I don't much like the frame it is attached to... )

cheers

[PJ520]

So I reckon you have three options for longer life;

1) try to make the hollowtech stuff last; I think that with the right approach (interior seals out, void filled with semi-fluid grease) the bearings ought to last a lot longer. Whether it is 'long enough' though, remains to be seen. A Hope BB is also a good approach (although it is not an inexpensive part).
2) get a new ST setup
3) Have your old cranks dye-penetrant inspected; if they are not cracked then they should have a few years left in them yet.

Thanks Brucey.
1) Sounds most promising right now. I have a 2300 mile tour coming up starting in May. It'll be interesting to see if I have the same experience as TrevA. If I do have that experience I think it will be worth investing in a Hope BB when the Shimano claps out. I must say I rather like the feel of the Hollowtech stuff, possibly in large part due to the old phenomenon of not realizing how bad the original had got due to slow wear over 1000s of miles.
2) possible
3) impossible I tossed 'em. Silly me.

[TrevA]

It depends. Presumably your old chainset is a square taper type. If it is, then you might get away with just changing the chainset. New bottom brackets are less than £20 anyway - go for a Shimano UN55 in the width recommended by Spa on their website. The Shimano one will last much longer than a Stronglight one. You might have to move your front mech done a bit, to maintain a smooth change. I swapped a 50/39/30 hollow tech II triple for a Spa square taper 48/38/28. I got sick of replacing the bearings on the Hollowtech every 2-3000 miles. Shimano square taper BB has done 10000 miles so far with no problems - Stronglight one lasted less than a year (about 3000 miles).

This is bad news for me as I've just been talked into installing a 105 Hollowtech triple, the square taper BB that came with the bike had 51,000 miles on before it started to wobble it but it looks like I'm going to get nowhere close to that out of the new stuff. FWIW I'm using 50-39-24 with 11-32 at the back. The 105 front shifting is silky smooth but it looks like bearing changes are in my near(ish) future. My LBS told me that square taper cranks are no longer available. Is that correct? If the Hollowtechs last as short as people say I want to go back to the old stuff. The reason I changed the cranks was paranoia about crank breakage after so many miles.

Replacing the External bearings is not a difficult job. Takes about 15 mins. It's just that I have 6 bikes to look after, so the problem is multiplied. Hollowtech chainsets do flex less, so there is some advantage to sticking with it, but the "fit and forget" square taper won the day for me, especially on my winter bike, where I'm not so bothered about going fast.