different chain rings on Shimano road double and triple cran

[aurelome]

1) Does anyone know why Shimano puts different rings on road triples than on road doubles? Doubles seem to come with 53/39 combos, while triples come with 52/42/30. This seems odd to me; why not just add a third ring and leave the other two the same? Is it a silly marketing thing, or is there a good technical reason for this?

So of course, I'd like to change the rings on a recently acquired Ultegra triple to 53/39/30 (or perhaps even a 28 small ring). My LBS tells me that the rings are actually different and that such a change would be
"difficult." So...

2) Is this true, or can I easily change my triple rings to double rings?

And question 3 of my two questions: if I have the long cage Ultegra derailleur, can I use an old (unused) 28 Shimano MTB ring I have kicking around, or is the small ring road specific?

[nelsius]

Ah yes, but for 10-speeds or just 9? Eventually I'd love to have just one cassette that does it all, and I think I'll need a 10 for that. 12-29.
That's all I ask. 12-13-14-15-17-19-21-23-26-29 or something like that!

[Szeliga98]

Try a 'Tyler crank'. 50/34..I know it ain't shimano and Wayne may not send ya a free shimano t-shirt, but it will solve some of your gearing 'problems'...

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302 (303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

[bljack]

Dear Arthur and Mike,

Come, come, fellows, let's not squabble about a few teeth during the holidays!

As a friend often remarked at the Honda shop, it's easy enough to grind off a gear tooth or two--surely that will fix things, won't it?

[Szeliga98]

He did altho i heard it was a 53(perhaps a 52) and a 36...

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302 (303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

[Szeliga98]

Mike-<< Yeah, but what would Peter Chisholm say if I moved away from Shimano and used Campy? >>

Hoooray? and I'll give ya a free Campagnolo tshirt.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302 (303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

[cat_on_my_head]

Or at least some of the Powers That Be seem to believe so. I think they all must live in someplace like Miami, where the only way to find a 300-foot elevation climb would be by riding up the fire escape stairwell of an office building that had one with a handicapped ramp.
(As if you'll find one!) (100 feet can be had in a few parking garages, if you don't get arrested for trespassing.)

(Of course, I shouldn't say too much; I'm in Houston, and just 75 feet above sea level...)

But...but...if they had lesser gears than their idols, how would they ever be able to think they could achieve the same feats?

(The dodge, of course, is to buy a touring bike; selected carefully, it has all the looks of a road bike, but with a 75% greater gear range...or more.)

Would that be a 24/34 bailout combo on an mtb?
I ended up with that combo on a bike last week for a couple of days; I was swapping wheels around to optimize a couple of things on other units, and a 14-34 cassette ended up on the bike with the 24/34/44 triple. I think I could probably have pulled a loaded tandem up a grade with it. Not very *fast*, but the effect of the mechanical advantage was immediately evident.

[Niflheim]

That explains why standard road triples went to a 10T difference. Wh
52/42 instead of say 53/43 or 54/44

-

[Szeliga98]

rick-<< Really, the triple's largest is a 52 while the double's is a 53.

Top three Campagnolo triples start with a 53..not that I think a 53 is a good idea...I still use a 50t big ring.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302 (303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

[Szeliga98]

byron-<< 1) Does anyone know why Shimano puts different rings on road triples than on road doubles? Doubles seem to come with 53/39 combos, while triples come with 52/42/30. This seems odd to me; why not just add a third ring and leave the other two the same? >>

With a well set up triple, where you can use the middle with the entire cogset range, a 42 is more useable than a 39, IMO, YMMV.

byron<< So of course, I'd like to change the rings on a recently acquired triple to 53/39/30 (or perhaps even a 28 small ring). My LBS tells me that the rings are actually different and that such a change would be
"difficult." >>

If you use a 39t with pickup pins and ramps it will work fine, use a TA. If you just put a road 39t on there, it may not shift well as shimano triples really rely on the pins and ramps.

bryon- <>

if it is 74mm BCD, it'll work.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302 (303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"