About three months ago I bought a Boardman MTX8.8 Hybrid bike which overall I'm quite happy with.
https://www.boardmanbikes.com/gb_en/pro ... x-8.8.html
The exception is the compact double chainset (48/32) which I just cannot get on with. There is just too much of a jump for me when swapping the front cogs. I've given it a fair chance but have concluded that I really don't like it and I'd like to convert it to a triple.
I've done this before on other bikes, the best example being a 1984 Peugeot (what was a 12 speed racer) into a 24 speed racer!
I'm fairly certain I can deal with measuring and working out a revised bottom bracket on the Boardman, the current chainline is very tight so a new BB is a given. I also believe the deore thumbshifter will work with a triple as well and hope the front cog swapper has enough throw! I'm also aware that I may need to change the medium cage rear derailleur to a long cage version also.
The thing I'm not sure about is the front coggage as this is my first 10 speed rear cogged machine which I believe has a fragile narrow chain. I don't know if there is an off the shelf option ready to fit (square taper) but believe it may be difficult to find one that will work with a ten speed chain? I'm therefore thinking about binning the smaller front cog and adding a new middle and small cog.
My plan would be to have a 48/38/28 front cog set where the 48 is already present and where I'd need to source the 38 and 28 along with any bits and bobs. With regard to those bits and bobs, what would I need, spacers, bolts etc?
Any advice or information would be very much appreciated and any links to stuff I can buy to carry out the conversion even better. As above I can contend with the BB and rear derailleur but it is the front coggage I'm stuck on.
Compact double to triple conversion
Re: Compact double to triple conversion
I think you'll need to be careful about compatibility - I don't think your existing rings will fit on a triple, and it will be cheaper to buy a chainset comnplete anyway - e.g. spa cycles have a good selection. You'll probably need a new BB, and probably front mech and shifter I would think?
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chris_suffolk
- Posts: 738
- Joined: 18 Oct 2012, 10:01pm
Re: Compact double to triple conversion
I understand that you've given it a while, and can't get on as the jump between front rings gives too much of a jump in gearing, but....
Unless the manufacturer has got it totally wrong (which is possible but unlikely) then there should be a good run of gears when switching the front, so long as you switch in the opposite direction at the back at the same time.
I'm running a compact front with a 11 - 32 9 speed rear. If I switch front cogs I need to move the rear 3 jumps to get the same gear. So if I'm climbing and want 1 gear easier, it's move front to small, and move rear 2 cogs smaller at the same time. The reverse being true when wanting a faster gear - front to large and 2 cogs larger at the rear.
I strongly suspect that the same is true of pretty much any off the shelf group-set, be it road, MTB or in between.
What front and rear tooth counts do you have?
Unless the manufacturer has got it totally wrong (which is possible but unlikely) then there should be a good run of gears when switching the front, so long as you switch in the opposite direction at the back at the same time.
I'm running a compact front with a 11 - 32 9 speed rear. If I switch front cogs I need to move the rear 3 jumps to get the same gear. So if I'm climbing and want 1 gear easier, it's move front to small, and move rear 2 cogs smaller at the same time. The reverse being true when wanting a faster gear - front to large and 2 cogs larger at the rear.
I strongly suspect that the same is true of pretty much any off the shelf group-set, be it road, MTB or in between.
What front and rear tooth counts do you have?
Re: Compact double to triple conversion
If the problem is the jump 32 to 48 you cold buy a 36 tooth chainring for £22.90
https://www.ebay.co.uk/p/10009073146?ii ... 1910151943
https://www.ebay.co.uk/p/10009073146?ii ... 1910151943
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simonineaston
- Posts: 8063
- Joined: 9 May 2007, 1:06pm
- Location: ...at a cricket ground
Re: Compact double to triple conversion
Your proposed solution of changing to a triple chainset seems like a hammer to crack a nut. Surely a different inner ring (and possibly a different rear cassette...) is simpler & cheaper? And certainly, if you just pop on the new inner ring, quicker to impliment.There is just too much of a jump for me when swapping the front cogs
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Re: Compact double to triple conversion
I don't understand your problem,if the 24.5 to 120inches(48/32 × 11-36 cassette Boardman website)range is wide enough it's just a matter of using front and rear deraileurs at the correct time(double shifting).
If there's anything wrong with that drivetrain it's the 48t chainring that's too big making the bike grossely over geared for a bike of that type.
A 48x11 = 120 inch top gear with the standard 700x37 tyres = 32mph @90rpm cadence which is going some on any bike let alone a hybrid with an ordinary mortal on board.
If it were me I'd be considering a 44t outer ring which would still be 110inches 29.5mph @90 rpm but would bring the changes between rings much closer,or even a 42t outer would give you an even more usable top gear of 105inches,28mph @90rpm and an even closer difference between rings.
The other plus of a smaller outer ring would be a straighter chainline in the most used gears.
If there's anything wrong with that drivetrain it's the 48t chainring that's too big making the bike grossely over geared for a bike of that type.
A 48x11 = 120 inch top gear with the standard 700x37 tyres = 32mph @90rpm cadence which is going some on any bike let alone a hybrid with an ordinary mortal on board.
If it were me I'd be considering a 44t outer ring which would still be 110inches 29.5mph @90 rpm but would bring the changes between rings much closer,or even a 42t outer would give you an even more usable top gear of 105inches,28mph @90rpm and an even closer difference between rings.
The other plus of a smaller outer ring would be a straighter chainline in the most used gears.
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"All we are not stares back at what we are"
W H Auden
"All we are not stares back at what we are"
W H Auden
Re: Compact double to triple conversion
reohn2 wrote:I don't understand your problem,if the 24.5 to 120inches(48/32 × 11-36 cassette Boardman website)range is wide enough it's just a matter of using front and rear deraileurs at the correct time(double shifting).
If there's anything wrong with that drivetrain it's the 48t chainring that's too big making the bike grossely over geared for a bike of that type.
A 48x11 = 120 inch top gear with the standard 700x37 tyres = 32mph @90rpm cadence which is going some on any bike let alone a hybrid with an ordinary mortal on board.
If it were me I'd be considering a 44t outer ring which would still be 110inches 29.5mph @90 rpm but would bring the changes between rings much closer,or even a 42t outer would give you an even more usable top gear of 105inches,28mph @90rpm and an even closer difference between rings.
The other plus of a smaller outer ring would be a straighter chainline in the most used gears.
More expensive than changing the inner but certainly cheaper than new b/b, chainset and possibly mechs and shifters. As you say quite possibly more suitable for most people than the 120 " gear the OP currently has. I rode my old road racing bike today with a 119" gear and got to 40 mph and wasn't spinning out.
https://www.ebay.co.uk/p/20011035167?iid=273132786493
Re: Compact double to triple conversion
All responses so far are very much appreciated, thank you.
In consideration of them, I'm leaning towards keeping the front as a double but reducing the size of both cogs.
I'm on an elephant tranquilising dose of beta blockers which makes the tallest gears largely irrelevant anyway, I'd rather have, and need, more gear choice at the lower end.
According to this...
https://shop.fullspeedahead.com/en/vero ... nkset-3976
The BCD is 120 with four holes, so the choice is seemingly limited, well at least from a bit of e-bay searching.
In consideration of them, I'm leaning towards keeping the front as a double but reducing the size of both cogs.
I'm on an elephant tranquilising dose of beta blockers which makes the tallest gears largely irrelevant anyway, I'd rather have, and need, more gear choice at the lower end.
According to this...
https://shop.fullspeedahead.com/en/vero ... nkset-3976
The BCD is 120 with four holes, so the choice is seemingly limited, well at least from a bit of e-bay searching.
Re: Compact double to triple conversion
This double chainset with your choice of rings:- https://www.spacycles.co.uk/m2b0s109p33 ... cral-Rings
With a Shimano UN55 115mm BB
Will lower your overall gearing considerably and should work with your existing shifter and front deraileur.
With a Shimano UN55 115mm BB
Will lower your overall gearing considerably and should work with your existing shifter and front deraileur.
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"All we are not stares back at what we are"
W H Auden
"All we are not stares back at what we are"
W H Auden
Re: Compact double to triple conversion
Gear ratios seem to be far too high these days. Perhaps there is some justification for competition riding, 40mph pro sprint finishes.
In 1988 I bought a Raleigh Road Ace, which was their top, off the peg road bike. It was fitted with the a 52 x 13 top gear, standard at the time.
A 44 x 11 is exactly the same ratio. Arguably still a higher gear than is needed for general riding.
In 1988 I bought a Raleigh Road Ace, which was their top, off the peg road bike. It was fitted with the a 52 x 13 top gear, standard at the time.
A 44 x 11 is exactly the same ratio. Arguably still a higher gear than is needed for general riding.
Re: Compact double to triple conversion
I just switched my partner's setup from 36-50 double to the spa XD-2 triple for touring reasons - https://www.spacycles.co.uk/m2b0s109p2000/SPA-CYCLES-XD-2-Touring-Triple-Chainset
The cost did mount up - new 110mm bottom bracket, long cage derailleur plus the chianset. Luckily the front shifter is friction and the front derailleur works fine. Works great.. just need to get touring now..
The cost did mount up - new 110mm bottom bracket, long cage derailleur plus the chianset. Luckily the front shifter is friction and the front derailleur works fine. Works great.. just need to get touring now..
Re: Compact double to triple conversion
I've been thinking of doing the same. Looking for guidance on possible issues.
I've got a 50-34 compact crankset on 9 speed Tiagra. I recall the Tiagra STI (c. 2010) was interchangable with double/triple and the shop I bought from said the same thing.
The front derailleur shifter shows three markings reinforcing this. Assuming I buy two compatible inner rings to replace the 34t, am I right in thinking that I simply adjust the high/low screws of the FD?
It's a Hollowtech BB and they all come in a standard size (I think), so won't need to change this?
I've got a 50-34 compact crankset on 9 speed Tiagra. I recall the Tiagra STI (c. 2010) was interchangable with double/triple and the shop I bought from said the same thing.
The front derailleur shifter shows three markings reinforcing this. Assuming I buy two compatible inner rings to replace the 34t, am I right in thinking that I simply adjust the high/low screws of the FD?
It's a Hollowtech BB and they all come in a standard size (I think), so won't need to change this?
Last edited by Cyclewala on 29 May 2020, 12:17pm, edited 2 times in total.
Re: Compact double to triple conversion
I too would recommend the Spa Compact that reohn2 has suggested. I would also suggest you consider the following:
1. What gear(s) do you normally find yourself using when riding along on the flat mid ride? That should determine the large chainring size you should get, based on the chain being in or close to the middle of the cassette.
2. The 16 tooth difference of your 48/32 chainset is replicated by the Spa compact chainsets. That is because most Shimano front derailleurs are designed for that interval. So you will have a similar large jump when changing at the front with most chainsets, and as commented above you should normally expect to make a double shift when changing at the front, i.e. change at the back as well.
You can often get away with changing the tooth difference between the front chainrings, but how successful this is will probably depend on the amount of the change, the tolerance of your particular bike and components to such a change, how much effort you put in to getting the gears working optimally, and how much you are will to tolerate less than perfect front shifting. A 14 tooth difference will probably be no problem, but the more you reduce the interval the more you may find the shifting less to your satisfaction and/or will need to fiddle with the height of the front mech to get the best from your chosen combination.
I guess if you ask, Spa might be willing to swap the inner ring of a compact chainset for a larger one, e.g. change 44/28 to 44/30 or 44/32.
3. You can use this website to see the differences between your current gearing and possible alternatives. I've already input your current gearing in the link together with a 40/24 chainset for comparison.
4. Note that some front deraillers, especially those with a long cage, may foul on the chainstay if lowered a lot, e.g. to accommodate a 24 tooth inner.
1. What gear(s) do you normally find yourself using when riding along on the flat mid ride? That should determine the large chainring size you should get, based on the chain being in or close to the middle of the cassette.
2. The 16 tooth difference of your 48/32 chainset is replicated by the Spa compact chainsets. That is because most Shimano front derailleurs are designed for that interval. So you will have a similar large jump when changing at the front with most chainsets, and as commented above you should normally expect to make a double shift when changing at the front, i.e. change at the back as well.
You can often get away with changing the tooth difference between the front chainrings, but how successful this is will probably depend on the amount of the change, the tolerance of your particular bike and components to such a change, how much effort you put in to getting the gears working optimally, and how much you are will to tolerate less than perfect front shifting. A 14 tooth difference will probably be no problem, but the more you reduce the interval the more you may find the shifting less to your satisfaction and/or will need to fiddle with the height of the front mech to get the best from your chosen combination.
I guess if you ask, Spa might be willing to swap the inner ring of a compact chainset for a larger one, e.g. change 44/28 to 44/30 or 44/32.
3. You can use this website to see the differences between your current gearing and possible alternatives. I've already input your current gearing in the link together with a 40/24 chainset for comparison.
4. Note that some front deraillers, especially those with a long cage, may foul on the chainstay if lowered a lot, e.g. to accommodate a 24 tooth inner.
Re: Compact double to triple conversion
48 sounds too high from your description.
I moved from a 52/42/30 triple to 44/30 this year, and couldn't be happier with the setup.
I use the 30 far more than I did with the triple, where I treated it as a 'bail out' gear on the bottom two sprockets. FWIW, I ride just as quickly with a 44 as with a 50 or 52 ring.
When triples were in common use, the top rear sprocket was a 12. Now with the top rear sprocket being an 11, you simply don't need chainrings of 48/50/52/53. I expect even Eddy Merckx didn't ride 52/11.
Also, in my 20years of triple experience, Campag admittedly, moving to a triple is a real PITA, when you need to change shifters as well as mechs. Far simpler to change the chainset.
Of course everyones opinion will differ, but this is my experience.
Good luck!
I moved from a 52/42/30 triple to 44/30 this year, and couldn't be happier with the setup.
I use the 30 far more than I did with the triple, where I treated it as a 'bail out' gear on the bottom two sprockets. FWIW, I ride just as quickly with a 44 as with a 50 or 52 ring.
When triples were in common use, the top rear sprocket was a 12. Now with the top rear sprocket being an 11, you simply don't need chainrings of 48/50/52/53. I expect even Eddy Merckx didn't ride 52/11.
Also, in my 20years of triple experience, Campag admittedly, moving to a triple is a real PITA, when you need to change shifters as well as mechs. Far simpler to change the chainset.
Of course everyones opinion will differ, but this is my experience.
Good luck!