Bicycle Mechanics - triple to double?

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View Full Version : triple to double?


Turboem1
09-21-06, 07:13 PM
Just wondering what would be involved in changing an 06 lemond reno from a triple to double? What parts would have to be changed? Thanks


dbs
09-21-06, 08:03 PM
look at your spindle length.

Al1943
09-21-06, 08:13 PM
Generally this requires a new crankset, bottom bracket, and both derailleurs. Depending on what type of shifters you now have they may or may not need to be replaced. Need to know the group and speeds.
Or you can remove the granny chainring, adjust the low limit screw and call it a double, but you havn't really gained anything by doing that.

Al


Turboem1
09-23-06, 07:49 PM
Its a 2006 Lemond Reno. It was offered in double and triple if that makes a difference. Anyway here are the specs...

Front Derailleur Shimano Tiagra
Rear Derailleur Shimano 105
Shifters Shimano Tiagra STI
Cassette Sram PG950 11-26 9spd
Bottom Bracket TruVativ ISIS Giga Pipe
Crank Bontrager Select

oilman_15106
09-23-06, 09:06 PM
If the intent is to save weight, it is not enough savings vs. the expense of chaning the setup. Why do you want to change it to a double?

Phoible
09-23-06, 11:42 PM
You may be able to find a double crank that fits on your existing bottom bracket. Make sure that the chainline is correct - otherwise, you may not be able to get your front derailleur to shift properly.

If you can find such a crank, you may be able to get the rest of your setup to work.

You shouldn't need to replace your rear derailleur, and you should be able to adjust your front derailleur to shift a double properly.

http://www.velonews.com/tech/report/articles/9053.0.html

Retro Grouch
09-24-06, 07:19 AM
Just wondering what would be involved in changing an 06 lemond reno from a triple to double? What parts would have to be changed? Thanks

What are you trying to accomplish?

If your goal is to make it look like a factory double you'll need a new crankset, new bottom bracket and new front a d rear derailleur.

Short of that there are a number of things you can try. For example, you could buy just a double crankset bottom bracket, remove your granny ring, reinstall your existing crankset and readjust your existing front derailleur. That's probably the cheapest solution that would have any benefit at all.

If you're looking for a real world performance improvement, I wouldn't expect much.

Turboem1
09-24-06, 07:33 AM
well i bought a triple and i hear people say doubles are better and have smoother shifting. I am just seeing what is involved in case i do decide to change, which i most likely wont.

Retro Grouch
09-24-06, 07:50 AM
well i bought a triple and i hear people say doubles are better and have smoother shifting. I am just seeing what is involved in case i do decide to change, which i most likely wont.

So honestly, how often do you shift your front derailleur? That's the upper limit on any performance improvement that you can realize. Depending on where and how you ride, you might go for hours without making a front shift.

Balancing that is the loss of gear ratio range - usually the easier hill climb gears. If you never use the granny gear, it might not matter to you. If you ride steep hills, even occassionally, it might be a biggie. Nobody else can tell you what gears you need.

Relative to actual front shifting crispness, currently I've got a triple on my tandem and a 50/34 compact double on my road bike. I used to have a conventional 53/39 on the road bike. Honestly, I've not been able to sense much shifting performance difference among them.

A double crankset will buy you a few coolness points, but you'll have to do the complete factory conversion to get them.

DMF
09-24-06, 09:24 AM
Here are Shimano's compatibility charts:

Road front drive (http://bike.shimano.com/publish/content/cycle/sac/us/en/technical_service/compatibility_charts/road_compatibility.-MainContent-0001-DownloadFile.tmp/Front%20drive%20road%20compatibility.pdf.pdf)
Road rear drive (http://bike.shimano.com/publish/content/cycle/sac/us/en/technical_service/compatibility_charts/road_compatibility.-MainContent-0001-DownloadFile.tmp/Rear%20drive%20road%20compatibility.pdf.pdf)

Note that while you need to change derailleurs to go from double to triple, you may not need to change them to go from triple to double (in your case you don't). So you would need a crankset and bottom bracket. If you want to stay in the Tiagra/9-speed 105 universe, <$150 plus labor.

Still, I don't see the point.

Turboem1
09-24-06, 12:40 PM
so if theres no point why do they offer a double and a triple?
and why do you get cool points for a double?

thanks for the help!

Retro Grouch
09-24-06, 01:08 PM
so if theres no point why do they offer a double and a triple?
and why do you get cool points for a double?

Hey. I just describe the world as I see it. I don't try to make sense out of it.

MSL77384
09-24-06, 06:21 PM
Keep the triple. There are no "Style Points" on a hill when your legs feel like rubber and that granny ring is the difference between walking and riding up the hill.

dbg
09-24-06, 06:59 PM
Keep the triple. There are no "Style Points" on a hill when your legs feel like rubber and that granny ring is the difference between walking and riding up the hill.

+1. I change more people from double to triple than vice versa. Style points penalty for walking way exceeds the penalty for having a granny. I'll tell you what I tell everyone who wants to change from double to triple. ..Why don't you just not use the granny and spend the money on some cool bibs.

dbg
09-24-06, 07:00 PM
oops. make that "triple-to-doubel"

dbg
09-24-06, 07:00 PM
oops. make that "double" (too much wine with dinner)

Al1943
09-24-06, 07:13 PM
Its a 2006 Lemond Reno. It was offered in double and triple if that makes a difference. Anyway here are the specs...

Front Derailleur Shimano Tiagra
Rear Derailleur Shimano 105
Shifters Shimano Tiagra STI
Cassette Sram PG950 11-26 9spd
Bottom Bracket TruVativ ISIS Giga Pipe
Crank Bontrager Select

Tiagra 9-speed shifters are double/triple compatible (the reason I asked).