Triple to compact double?

xbenhanleyx

Hi, I am currently setting up a bike for my partner and want to use existing spare parts as much as possible, so that I can invest more in the frame. I am used to riding a double so all the parts I have are for double set up. However, my partner wants the lower gears of a triple (30/42).

Baring in mind that she never uses the large chainring (50), can I just buy a triple chainset and remove the 50 ring? Would I also need to buy a triple bottom bracket?

Thanks, Ben

SteveR_100Milers

You could just get a compact and fit smaller rings - 48 and a 34 would work ok, maybe you could increase the size of the rear cassette to get equivalent ratios?

xbenhanleyx

Its already 32 on the back! I was hoping that I could just remove the outer ring on one of our existing triple chainsets. I really want a 30 front - 32 back.

Bugly

xbenhanleyx wrote:

Hi, I am currently setting up a bike for my partner and want to use existing spare parts as much as possible, so that I can invest more in the frame. I am used to riding a double so all the parts I have are for double set up. However, my partner wants the lower gears of a triple (30/42).

Baring in mind that she never uses the large chainring (50), can I just buy a triple chainset and remove the 50 ring? Would I also need to buy a triple bottom bracket?

Thanks, Ben

Re bottom bracket - the answer is yes as the granny ring would be the problem not the outer - using a shorter BBwould result in the Granny ring either rubbing on your stays or being so close that your chain may be an issue. I cant see much advantage of removing the outer rings on the triple.

Bugly

xbenhanleyx wrote:

Hi, I am currently setting up a bike for my partner and want to use existing spare parts as much as possible, so that I can invest more in the frame. I am used to riding a double so all the parts I have are for double set up. However, my partner wants the lower gears of a triple (30/42).

Baring in mind that she never uses the large chainring (50), can I just buy a triple chainset and remove the 50 ring? Would I also need to buy a triple bottom bracket?

Thanks, Ben

Re bottom bracket - the answer is yes as the granny ring would be the problem not the outer - using a shorter BBwould result in the Granny ring either rubbing on your stays or being so close that your chain may be an issue. I cant see much advantage of removing the outer rings on the triple.

aracer

One possible alternative if you're looking at buying a new chainset (not quite clear whether that's the plan or you're adapting something you already have) is to get a MTB double - these typically come with 29-42. I suspect there may not be a cheap version of one of these, in which case the alternative is an MTB compact (5-bolt - 4-bolt MTB will only allow you to use a 32 middle ring, whilst 5 goes down to 29) minus the inner ring. That you could put on a shorter than normal BB, since there is no longer an inner ring to foul. The advantage over taking the outer ring off a road triple is that the pedals should be closer to the centre line.

In any case, you'll probably find that a standard road front mech doesn't work that well with a 42 outer ring - an MTB one would be much better.

maddog 2

if you want two rings with a smallest ring of (about) 30 then you have two main options:

1. Remove the outer ring of a road triple (as you say).

Good points - cheap. You'll need shorter c/ring bolts though.
Bad points - will look a bit odd and the pedals will be as wide as a triple anyway.

2. Fit a mtb double (as said) see Middleburn Duo (not cheap) and Stronglight Oxale.

Good points - better Q factor. Looks.
Bad points - cost.

The other option is the MTB triple route. You'd need a mtb front mech though - which will be a problem if you run road STI levers as they're not compatible.

xbenhanleyx

Thanks for the advice, I will go for the Oxale - not too expenive and a neater way of doing things.

Thanks,
Ben