Supercompact 46-30 Chainset on Road Bike

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Vaughan
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Joined: 25 Aug 2022, 4:39pm

Supercompact 46-30 Chainset on Road Bike

Post by Vaughan »

I have a 10 speed Ribble R872 carbon road bike with the following Campag components:

Veloce Powertorque compact crankset 50-34
Xenon Ergopower levers
Centaur 12-30 cassette
Veloce medium rear derailleur
Veloce double front derailleur

Although these gears have served me well, I now find that I rarely use the top two gears (50-12 and 50-13) but would like a lower bottom gear. I would like to keep the close ratios that the cassette provides and have been considering changing the crankset to a super-compact 46-30. This would still leave me with a more-than-adequate 105" top gear and give me a bottom gear of 27.5" compared with the existing 31.3". My local bike shop first suggested a Middleburn R02 x-type crankset, but the 46 and 30 chainrings do not seem to be available at present. There are Shimano GRX 600 46/30 sets available (albeit on a 5 week delivery), but I am concerned about compatibility. I would like to keep the front derailleur which looks like it has enough travel in the hanger to move down by the 8 mm needed to reach the smaller crankset. But I am not sure that it has enough travel to reach the outer ring on the GRX 600 which has a 2.5 mm wider chainline. I could also change to a compatible front derailleur (e.g. Shimano RX810), but this may need more pull than my Ergopower lever can give.

Can anyone advise if there is a suitable option for a 46-30 super-compact chainset on this bike?
Many Thanks.
Last edited by Vaughan on 25 Aug 2022, 6:58pm, edited 1 time in total.
geocycle
Posts: 2177
Joined: 11 Jan 2007, 9:46am

Re: Supercompact 40-36 Chainset on Road Bike

Post by geocycle »

I have a spa super compact chain set with 44/28. It runs with my shimano 105 derailleurs and shifters. I had to change to a square taper BB. I’m not sure about campag compatibility, but a call to Spa would confirm.
scottg
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Location: Highland Heights Kentucky,, USA

Re: Supercompact 40-36 Chainset on Road Bike

Post by scottg »

I tried the Shimano 810 front mech with 10s Ergo, way too much force needed to move the cage,
didn't get it to click, felt like the shifter might break.

Used the IRD/Microshift Sub-Compact mech instead.
https://www.rivbike.com/products/front- ... c-braze-on
46/30 Sugino crankset.
+++++++++++++++++++++++++
Deutsche Luftschiffahrts-AG
+++++++++++++++++++++++++
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TrevA
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Location: Nottingham

Re: Supercompact 40-36 Chainset on Road Bike

Post by TrevA »

I changed the chainset on my son’s Campag equipped bike - Mirage groupset, I swapped the standard 53/39 to a Stronglight 42/32 without changing any of the other components and it worked fine, so you should be ok with a 46/30 from Spa cycles. It’s square taper so you would need a new bottom bracket too, but everything else should work fine. I just moved the front mech down a bit and it didn’t foul the chainstay. This was on an Alu Pinarello.
Sherwood CC and Notts CTC.
A cart horse trapped in the body of a man.
http://www.jogler2009.blogspot.com
GideonReade
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Re: Supercompact 40-36 Chainset on Road Bike

Post by GideonReade »

TrevA wrote: 25 Aug 2022, 6:36pm I changed the chainset on my son’s Campag equipped bike - Mirage groupset, I swapped the standard 53/39 to a Stronglight 42/32 without changing any of the other components and it worked fine, so you should be ok with a 46/30 from Spa cycles. It’s square taper so you would need a new bottom bracket too, but everything else should work fine. I just moved the front mech down a bit and it didn’t foul the chainstay. This was on an Alu Pinarello.
Can I ask, was this 9 or 10 or what speed? Asking as my 9 speed Pinnarelo has a 53/39 (and 11-23 and short cage mech), and while I really like the way it works, I'm not convinced I will always be able to cope with such high gears!
Keezx
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Location: The Netherlands

Re: Supercompact 46-30 Chainset on Road Bike

Post by Keezx »

What I did a couple of years ago:
Had already a SRAM S900 chainset, bought a 4 arm 104 mm bcd MTB spider for little money and 46 /28 chainrings (Ebay)
Spider did not fit 100%, but after some filing& grinding it did.
Jamesh
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Joined: 2 Jan 2017, 5:56pm

Re: Supercompact 46-30 Chainset on Road Bike

Post by Jamesh »

You'll have to change the BB btw.

Getting chainlines ok is a bit of a mine field tbh.
Richard of York
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Joined: 21 Mar 2021, 6:41pm

Re: Supercompact 40-36 Chainset on Road Bike

Post by Richard of York »

geocycle wrote: 25 Aug 2022, 5:30pm I have a spa super compact chain set with 44/28. It runs with my shimano 105 derailleurs and shifters. I had to change to a square taper BB. I’m not sure about campag compatibility, but a call to Spa would confirm.
I ride with a couple of friends who got super compacts from Spa cycles and are very happy with them. Ring size combos are customisable. Looking at similar for my winter bike.
NickJP
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Re: Supercompact 46-30 Chainset on Road Bike

Post by NickJP »

Vaughan wrote: 25 Aug 2022, 4:53pmMy local bike shop first suggested a Middleburn R02 x-type crankset, but the 46 and 30 chainrings do not seem to be available at present.
You can fit a 94BCD spider to the RO2 crankset and use rings of those sizes. Here's an RO2 crankset on one of my bikes with that spider and TA 42/29 chainrings. Spa sell 94BCD TA chainrings in 29 or 30 inner and 42-50 outer. The RO2 isn't cheap, but it's very nicely made and very pretty.
IMG_20180822_163836.jpg
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TrevA
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Re: Supercompact 40-36 Chainset on Road Bike

Post by TrevA »

GideonReade wrote: 25 Aug 2022, 7:19pm
TrevA wrote: 25 Aug 2022, 6:36pm I changed the chainset on my son’s Campag equipped bike - Mirage groupset, I swapped the standard 53/39 to a Stronglight 42/32 without changing any of the other components and it worked fine, so you should be ok with a 46/30 from Spa cycles. It’s square taper so you would need a new bottom bracket too, but everything else should work fine. I just moved the front mech down a bit and it didn’t foul the chainstay. This was on an Alu Pinarello.
Can I ask, was this 9 or 10 or what speed? Asking as my 9 speed Pinnarelo has a 53/39 (and 11-23 and short cage mech), and while I really like the way it works, I'm not convinced I will always be able to cope with such high gears!
His bike was 9 speed. It would work with 10 speed too. I currently ride a 50/34 chainset, but I too am considering swapping to a 46/30 or similar on my Specialized Allez.
Sherwood CC and Notts CTC.
A cart horse trapped in the body of a man.
http://www.jogler2009.blogspot.com
Vaughan
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Joined: 25 Aug 2022, 4:39pm

Re: Supercompact 46-30 Chainset on Road Bike

Post by Vaughan »

Many thanks for all the helpful suggestions. Judging by the rapid replies, this looks like a hot topic! I am particularly interested in the R02 option suggested by NickJP as it should allow me to keep my front derailleur and have a hollowtech BB. Can I ask where you bought the parts? Looking on the Activesport website, they seem to have the crank arms, spider and the elusive 46/30 Middleburn chainrings available as separate parts. I have now added a photo of my existing setup.
Attachments
20220825_155301.jpg
GideonReade
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Re: Supercompact 46-30 Chainset on Road Bike

Post by GideonReade »

Is that really four ally pop rivets, holding the FD onto the carbon down tube?

I've just replaced half the ditto that hold the gunwale onto an open canoe. The boat was used in salt water, admittedly, weekly at most, then parked for nearly a decade, washed by rain. They rotted through under the head. Still, on a bike, if they did, one could get the remains out by removing the saddle...
NickJP
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Re: Supercompact 46-30 Chainset on Road Bike

Post by NickJP »

Vaughan wrote: 25 Aug 2022, 11:41pmMany thanks for all the helpful suggestions. Judging by the rapid replies, this looks like a hot topic! I am particularly interested in the R02 option suggested by NickJP as it should allow me to keep my front derailleur and have a hollowtech BB. Can I ask where you bought the parts? Looking on the Activesport website, they seem to have the crank arms, spider and the elusive 46/30 Middleburn chainrings available as separate parts. I have now added a photo of my existing setup.
I bought the cranks and spider about four years ago from Activesport. I think I already had the chainrings - I have a pretty good stock of 94BCD rings as I use that size on several bikes.

BTW, if you ever decide on a smaller large chainring than the adjustment on a frame's braze-on derailleur hanger allows, Sugino and Wickwerks both sell adapters that allow the derailleur to be mounted lower than the braze-on hanger on its own allows. If you have a look on the image in my previous message, I used the Sugino adapter to get the FD down to the correct height for the 42t chainring. Here's a better photo of the adapter on one of my wife's bikes that has a 39t "big" chainring:
IMG_20180102_144900.jpg
TheBomber
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Re: Supercompact 46-30 Chainset on Road Bike

Post by TheBomber »

NickJP wrote: 25 Aug 2022, 10:01pm Spa sell 94BCD TA chainrings in 29 or 30 inner and 42-50 outer. The RO2 isn't cheap, but it's very nicely made and very pretty.
Nick - what chain speed are those TA rings being used with? I have a similar setup to the one the OP is looking for - Middleburn RO1 40x30 on a 10sp bike. I had trouble finding suitable 10sp 94bcd chainrings and noted that the TA ones are only described as 9sp. Eventually I found Middleburn rings that were described as 10sp but got chainsuck problems when shifting down at the front. The sort of problems that might have written off a carbon frame like the OPs. Speaking to BETD (new owner of Middleburn) it seems likely that my outer ring is not as sold - it’s actually 9sp. I don’t know how the TA rings will perform, but I’d be very wary of using them with a 10sp chain on a carbon bike. My problem was solved by changing chain brand from KMC to Shimano - anybody know what chain brand TA test their rings with?
Vaughan
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Joined: 25 Aug 2022, 4:39pm

Re: Supercompact 46-30 Chainset on Road Bike

Post by Vaughan »

Thanks Nick for the useful information.
And as for my hanger, yes it is held on with pop rivets. It came with these and I have had to replace them a couple of times over the eight years since I got the bike. I think there is a corrosion action between carbon and aluminium which affects the aluminium in preference. This is one reason (along with the £400 needed for the Middleburn upgrade) why I have also been looking to replace the bike and get a new one with carbon frame and supercompact gears. Most low gear bikes seem to come with compact chainsets and wide ratio cassettes, but I would prefer a close ratio cassette with 46/30 chainrings. I would appreciate any suggestions for a mid range road bike with such a set up.
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