Bicycle Mechanics - Cheapest way to get easier gearing on double chainring road bike

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joejack951
05-19-07, 05:39 PM
Here's the deal. I bought an old Trek road bike for my sister. It's currently a 6 speed freewheel (14-28) with a 52/42 double crankset. The area where we live tends to be hilly and I doubt she'll be able to handle those hills with a 42/28 low gear. So I'd like to change the gearing for her but given that I paid $40 for the bike and it will be a gift, I'd prefer not to sink too much money into it. She may decide after a few rides that she hates it anyway. So far, I've looked at the following options:

1. MTB triple crankset (very cheap) - I thought this was the perfect plan until I realized just how far off the chainlines are (should have checked into this before buying a crankset). I was hoping to use the 42 and 32 outer chainrings which would have given a decent range and not required anything but shortening the chain. Not going to work though. Oh well.

2. Compact road crankset (generally not so cheap) - Just today though I found an FSA square taper (big plus as I don't have to swap the BB) compact crank for ~$70. This has the most promise so far and may be the option I go with if nothing else is possible.

3. Wide range cassette - If I kept the same crank, I'd need something with a 34 tooth cog to even get close to the gear inches I think she'll need. To use a 34 tooth cog though, I'm swapping out the derailler and the chain. I could throw a little more money at it and put a 38 tooth chainring on the crank but the cost is really adding up now.

4. Touring crankset - I have yet to find a double chain ring touring crank. Does anyone make one?

5. Triple road crankset - This to me is the best option, especially for resale but there's just way too much to swap out then. I believe I'd need a new front downtube shifter (can anyone confirm this?) plus a front and rear derailler and chain and maybe a BB. The crank spider is drilled and tapped to accept a small inner ring so I wouldn't need a whole new crankset at least. I'm better off finding another bike then doing all that, I think.

Any other ideas are very appreciated. Anyone offering cheap parts for a triple conversion would also be welcomed to contact me.


Rev.Chuck
05-19-07, 07:53 PM
The cheapest is to replace the 42 with a 38(smallest size that will fit 130bcd) The next cheapest is to go with an MTB cheapo crankset and der, but there might be some der/shifter issues, maybe.

As you already have the compact crank, give that a go. I have one on a bike and it makes the climbs very easy.

joejack951
05-19-07, 07:56 PM
The cheapest is to replace the 42 with a 38(smallest size that will fit 130bcd) The next cheapest is to go with an MTB cheapo crankset and der, but there might be some der/shifter issues, maybe.

As you already have the compact crank, give that a go. I have one on a bike and it makes the climbs very easy.

I have the cheapo MTB crank but the chainline is way off trying to use it. It was only $30 compared to $70 for the compact (that I haven't bought yet but wish I had seen when I ordered the MTB crank). I can't think of any workaround for the chainline issue and I think the shifting and general performance will be affected by it being so badly misaligned.

The compact is looking better and better.


acorn_user
05-19-07, 07:57 PM
[QUOTE=joejack951]
1. MTB triple crankset (very cheap)

///also very ugly!


3. Wide range cassette

//e as cheap as chips. Use an Alivio derailleur. It will most likely be better than the one on their right now.

4. Touring crankset - I have yet to find a double chain ring touring crank. Does anyone make one?

//Yes, but most of them are called road doubles now. The Sugino XD is the number one choice. The TA Vega or Stronglight Oxale Two would be other examples...


5. Triple road crankset - This to me is the best option, especially for resale but there's just way too much to swap out then. I believe I'd need a new front downtube shifter (can anyone confirm this?) plus a front and rear derailler and chain and maybe a BB. The crank spider is drilled and tapped to accept a small inner ring so I wouldn't need a whole new crankset at least. I'm better off finding another bike then doing all that, I think.

///You need a new front mech, and possibly a new BB. You do not need a new chain or downtube shifter; the fron shifter will be in friction mode, so it doesn't care! It's only a few STI models that cannot accomodate both.

I do have a Campagnolo Veloce triple and matching mech around. Let me know if you are interested.

joejack951
05-19-07, 08:11 PM
///also very ugly!

//e as cheap as chips. Use an Alivio derailleur. It will most likely be better than the one on their right now.

//Yes, but most of them are called road doubles now. The Sugino XD is the number one choice. The TA Vega or Stronglight Oxale Two would be other examples...

///You need a new front mech, and possibly a new BB. You do not need a new chain or downtube shifter; the fron shifter will be in friction mode, so it doesn't care! It's only a few STI models that cannot accomodate both.

I do have a Campagnolo Veloce triple and matching mech around. Let me know if you are interested.

Yes, the MTB crank is an eye sore on the bike compared to the all silver period-looking Sugino crank.

Hmmm, maybe I should reconsider the wide range cassette. The crank currently on the bike has 165mm arms which I was hoping to keep. Swapping the inner ring for a 38 (~$20) plus adding the 7 speed wide range cassette (~$20) and new derailler (~$25) gets me some new parts, an extra gear, plus lower gearing than just adding the compact crank all for the price of the compact or less. I'm liking it. I'm not sure why I was so opposed to it earlier.

Thanks for the Campy triple offer but it appears that you are in the UK making shipping a bit expensive (unless you feel like giving those parts away :)). Do you have a BB to go with the crank?

Thanks for the reply.

Bill Kapaun
05-19-07, 08:35 PM
Why not let her just try it first?
I fixed my brother up with an old DiamondBack FleetStreak (MB) 12 speed---50-40 x 14-28. he has some moderate hills and says the worst he's had to gear down was 40-24. He only rides 2-5 miles about 3-4 times a week, so he's not super "bike fit". Your road bike should be a bit easier rolling. Enough to make up the difference in tire dia. anyway.

joejack951
05-19-07, 08:43 PM
Why not let her just try it first?
I fixed my brother up with an old DiamondBack FleetStreak (MB) 12 speed---50-40 x 14-28. he has some moderate hills and says the worst he's had to gear down was 40-24. He only rides 2-5 miles about 3-4 times a week, so he's not super "bike fit". Your road bike should be a bit easier rolling. Enough to make up the difference in tire dia. anyway.

I've biked on some of the same hills and was happy to have a 30-25 at times. I'm significantly more bike-fit than she is and only weigh about 25 lbs. more. You have a good point though. Perhaps I could get a hold of another bike that fits her that has gearing similar to what I'm trying to put together and see if it works. It's quite possible that a 38-34 still won't be enough (or maybe she'll surprise me and not need something quite so low) in which case I'm better off not wasting any time and money on the parts I've planned to order.

joejack951
05-19-07, 08:57 PM
Use an Alivio derailleur.

I was just checking out this derailleur and it's spec'd as having a max cog capacity of 30 teeth. Will it shift a 34 tooth cog? I know Shimano is a little conservative in their specs.

Retro Grouch
05-20-07, 06:35 AM
I think that the cheapest and easiest is to replace the freewheel with a 14 to 34 and install a mountain rear derailleur and a new, longer chain. I don't know exactly what Alivio deraailleur you are talking about but the current, M410, is rated for a 34 big cog.

Unless you're a lot luckier than me, your existing bottom bracket isn't going to work with a different crankset. After you replace the crankset you may also find that you have front derailleur issues.

joejack951
05-20-07, 07:24 AM
I think that the cheapest and easiest is to replace the freewheel with a 14 to 34 and install a mountain rear derailleur and a new, longer chain. I don't know exactly what Alivio deraailleur you are talking about but the current, M410, is rated for a 34 big cog.

Unless you're a lot luckier than me, your existing bottom bracket isn't going to work with a different crankset. After you replace the crankset you may find that you have front derailleur issues.

It was late and I was being dense. Nashbar has some 2006 version of the Alivio derailleur on their site that's only rated for a 30 tooth cog but the Alivio RD's that I've found elsewhere (which are M410's) are rated for 34 tooth cogs.

HillRider
05-20-07, 08:57 AM
Is the current crank a 110 bcd model? Many older double "road" cranks were. If so you could replace the 42T chainring with a 34T and, either keep the 52 or swap it for the 42.

joejack951
05-20-07, 09:12 AM
The current crank is a 130 bcd model. 38 appears to be the lowest that I can fit on it.

clancy98
05-20-07, 09:19 AM
just ride behind her and yell "tough it out, wuss!"

that will probably work ;)

joejack951
05-20-07, 09:28 AM
That'll go over really well while I'm spinning up the hill in the granny ring :)

DMF
05-20-07, 12:13 PM
2. Compact road crankset (generally not so cheap) - Just today though I found an FSA square taper (big plus as I don't have to swap the BB) compact crank
That may not be true. Different models of double/compact cranks often need different axle lengths.

CdCf
05-20-07, 12:59 PM
How about using the triple, but use the inner and middle only? That should solve most or all of the chainline issues, and you'd get really low gearings! :D

DieselDan
05-20-07, 02:52 PM
Try a cyclocross double with a 34/48 setup.

joejack951
05-20-07, 03:03 PM
How about using the triple, but use the inner and middle only? That should solve most or all of the chainline issues, and you'd get really low gearings! :D

I'd need a different bottom bracket to reposition the crank to get a good chainline using the two inner rings. Although, a basic square taper bottom bracket and a 30 tooth inner ring is a pretty cheap combo. I can't remember if there was some reason that I was shying away from doing this. It might be that I may run into issues trying to shift a 42/30 crankset with a standard road double front derailleur. Hmmmm, so many options now appearing...

joejack951
05-20-07, 03:04 PM
Try a cyclocross double with a 34/48 setup.

Do you know of any cheap ones? I haven't come across any in my searching. The cheapest new crank that would work that I found was $70 (compact double 50/34).

bfromcolo
05-20-07, 05:09 PM
I just did this to my own 89 Trek 400. New 38 tooth FSA chainring $12 on eBay, new Deore long cage derailler $15 eBay, new 13-32 7 speed freewheel $18 Nashbar, and Nashbar threw in a new chain. So thats $45, actually about $60 with shipping. The 38-32 combo is a nice improvement over the 42-28.

I also replaced the big chainring when I saw one on a bargain table at a bike shop in town, but everything worked fine with the original 52 tooth elliptical.

The other benefit is with all this new hardware it shifts and rides very smoothly. I did have to go to friction mode on the rear shifter (the front was friction from the start), not sure if it didn't like the derailler or the big ring, but it had issues with the big cog indexed.

B

acorn_user
05-20-07, 06:30 PM
I would have thought that the Alivio would work with a 34t cog. My bike had a 34t alpine freewheel and an Altus mech, so the Alivio should be fine. Deore would be a step up though. I have an LX on it right now, it that works very well.

I'm at UVA right now, so the cranks are located in fair Virginia. No bottom bracket though.