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-   -   Change from triple to a double chainring? (https://www.bikeforums.net/touring/626554-change-triple-double-chainring.html)

raydog 03-06-10 09:05 PM

Change from triple to a double chainring?
 
I have a 27 speed (Shimano Ultegra) and am switching from a 9 speed cassette to a 10. Here's my question.....On my upcoming long tour, with a Bob trailer (trlr and cargo 45 total lbs), would it be OK to go to a double front chainring. Without a trailer I never use the small sprocket and my 800 mile 8 day ride only has 20k of total elevation gain. I am in strong aerobic condition. Thanks for any opinions. Raydog

The Smokester 03-06-10 09:16 PM

Not enough information. How many gear-inches do you have now that you use and how many will you have after the switch. And how much weight is added for the tour. After that, it's just a simple calculation.

gorshkov 03-06-10 10:53 PM

My question is, why do you want to use a double? Since you already have the triple, I would stay with it. According to Sheldon Brown, a 10-speed chain should work with the current (9-speed designed) crankset.

To the best of my knowledge, the largest cog on a Shimano 10-speed cassette is 27 teeth, which with a compact double crank gives you a lowest gear of about 34 gear-inches, which imo is not low enough for loaded touring. For comparison, most purpose-built touring bikes have a low gear around 20 gear-inches.

raydog 03-07-10 12:05 AM


Originally Posted by gorshkov (Post 10491023)
My question is, why do you want to use a double? Since you already have the triple, I would stay with it. According to Sheldon Brown, a 10-speed chain should work with the current (9-speed designed) crankset.

To the best of my knowledge, the largest cog on a Shimano 10-speed cassette is 27 teeth, which with a compact double crank gives you a lowest gear of about 34 gear-inches, which imo is not low enough for loaded touring. For comparison, most purpose-built touring bikes have a low gear around 20 gear-inches.

That is the exact info I was looking for, and in the Mechanical section someone reminded me how much it would screw up the trip if I ran out of gear on the hills......thanks much. Raydog

vegenaise 03-07-10 01:20 AM

i run a compact double with a 10 in the rear. never had a problem with gearing on my tours. you'll make due with what you have. don't sell yourself short and settle in to mediocrity as most of the 50 year old tourers here have. man up and go for it.

dewaday 03-07-10 06:44 AM


Originally Posted by vegenaise (Post 10491329)
i run a compact double ...

gears are for sissies

gregw 03-07-10 08:38 AM


Originally Posted by vegenaise (Post 10491329)
i run a compact double with a 10 in the rear. never had a problem with gearing on my tours. you'll make due with what you have. don't sell yourself short and settle in to mediocrity as most of the 50 year old tourers here have. man up and go for it.

That whole "Right tool for the job" thing is way over rated! Why use the triple you have now when you could beat yourself up with a double? :twitchy:

kayakdiver 03-07-10 08:44 AM


Originally Posted by vegenaise (Post 10491329)
i run a compact double with a 10 in the rear. never had a problem with gearing on my tours. you'll make due with what you have. don't sell yourself short and settle in to mediocrity as most of the 50 year old tourers here have. man up and go for it.

Why use a compact double and not a fixie weak sauce? Man up mediocrity.

LeeG 03-07-10 08:57 AM


Originally Posted by dewaday (Post 10491597)
gears are for sissies

real men ride unicycles

gregw 03-07-10 09:09 AM


Originally Posted by LeeG (Post 10491888)
real men ride unicycles

Unicycle with clip-in pedals, backpack and helmet with propeller on top.

mattbicycle 03-07-10 09:44 AM

I'm not technically-minded at all and only know what feels right for me.

I can understand the dilemma if you're considering whether to suffer the expense and trouble of going from two chainrings to three. But if you've already got three, and the ten speed is compatible, I can't see any value in short-changing yourself. Are you hoping to save weight or make the gearing set-up simpler? I must be missing something here. Perhaps I am in over-my-head commenting... It just seems like taking the light bulbs out of your car's head and taillights because you aren't planning on driving at night :)

If you've got a burning desire to change something in preparation for the trip, buy a better saddle, upgrade the tyres or something else that will be useful!

Bekologist 03-07-10 10:20 AM

on your upcoming long tour, would it be ok to go to a double front chainring combo? why, sure.... just 20,000 elevation gain :eek: a double is definitely what you want for this.

why do you want to do go to the double again? You never use the little ring?

Pretend you don't have it, until you absolutely, positively need it - that'll be fun!

raydog 03-07-10 10:51 AM

OK, this thread is funny, sarcastic, cynical and most importantly....informative. Why am I considering going to a double? The complete Ultegra (double front, 10 rear) system I just acquired is black chrome and my existing Ultegra (triple front, 9 rear) is polished silver handles. I realize that cosmetics/bling is the least important issue in the world compared to function/efficiency.
The shapes of the shifters are the same, just the finish is different. The reasons I was asking about going to the double are based on the racers I ride with on Computrainers (4 x's wkly). They all have doubles and I was asked once why I run a triple. I've been around bikes off and on for years BUT not bike culture much. I'm thinking the inquiry about my triple was grounded in, "real bikers don't need little chainrings, you whuse" elitism.

I really don't care if my handles don't match for this trip, the fact that I'm a 200 pounder with a trailer going 800 miles across Nevada and Utah should make it obvious to me.....keep the freeking triple. Doyle

10 Wheels 03-07-10 10:56 AM

How many of the racers were pulling a trailer?

blaise_f 03-07-10 11:43 AM


Originally Posted by raydog (Post 10492251)
OK, this thread is funny, sarcastic, cynical and most importantly....informative. Why am I considering going to a double? The complete Ultegra (double front, 10 rear) system I just acquired is black chrome and my existing Ultegra (triple front, 9 rear) is polished silver handles. I realize that cosmetics/bling is the least important issue in the world compared to function/efficiency.
The shapes of the shifters are the same, just the finish is different. The reasons I was asking about going to the double are based on the racers I ride with on Computrainers (4 x's wkly). They all have doubles and I was asked once why I run a triple. I've been around bikes off and on for years BUT not bike culture much. I'm thinking the inquiry about my triple was grounded in, "real bikers don't need little chainrings, you whuse" elitism.

I really don't care if my handles don't match for this trip, the fact that I'm a 200 pounder with a trailer going 800 miles across Nevada and Utah should make it obvious to me.....keep the freeking triple. Doyle

Roadies are more often than not the worst people to ask for advice on touring. Rarely do they "get" it. Why spend the time / effort to change to 2 though, when you already have 3 and you're hitting some killer hills, loaded. It's of course doable, but perhaps not your most enjoyable option. Having the gears lets you go lower if you want to. No one's forcing you onto that small ring though.

raydog 03-07-10 12:16 PM

Again, thanks to all of you for the discussion, this tour is already starting to be very fun! I just assembled my new Bob trailer and am loading it in the family room with my cargo. I have a doctor's scale and have weighed the trailer (me alone then me holding the trailer) @ 14 lbs. exactly. I've bought really light stuff (3 lb tent, 2 lb bag, etc.) and want to stay UNDER 50 lbs TOTAL trailer and ALL cargo, including water. Also, I took off the 50 psi tire and installed a 90 psi tire on the Bob (will use the 50psi for a spare).
SO, YOU TOURING EXPERTS, am I thinking clearly on all this? I so value your wisdom! Raydog

HardyWeinberg 03-07-10 12:33 PM


Originally Posted by raydog (Post 10492251)
OK, this thread is funny, sarcastic, cynical and most importantly....informative. Why am I considering going to a double? The complete Ultegra (double front, 10 rear) system I just acquired is black chrome and my existing Ultegra (triple front, 9 rear) is polished silver handles. I realize that cosmetics/bling is the least important issue in the world compared to function/efficiency.

Wow, a racing double, I was taking it for granted you meant a compact double which I figured could maybe get the job done w/ a 34t cog in the back. But I don't know if you can get a 10-spd cassette w/ a 34 in the back either. If this is an ultegra double/10 spd (27 or 28t large cog), I would be impressed with your fitness if you could use either component, never mind both, to pull a 45# trailer up any meaningful hill.

raydog 03-07-10 01:02 PM


Originally Posted by HardyWeinberg (Post 10492525)
Wow, a racing double, I was taking it for granted you meant a compact double which I figured could maybe get the job done w/ a 34t cog in the back. But I don't know if you can get a 10-spd cassette w/ a 34 in the back either. If this is an ultegra double/10 spd (27 or 28t large cog), I would be impressed with your fitness if you could use either component, never mind both, to pull a 45# trailer up any meaningful hill.

Yeah, we'll never know if I "pack the gear" to do the double because the triple is staying on the bike! Does 45 lbs. sound about right for sleeping on the ground, no cooking stuff (restaurants, mini marts and Cliff bars are the food plan) cargo load?

10 Wheels 03-07-10 01:09 PM

You might want take a trial camping trip one or two nights.
It is really the only way to test out everything you think you might need.

Less is Better.

raydog 03-07-10 01:45 PM


Originally Posted by 10 Wheels (Post 10492624)
You might want take a trial camping trip one or two nights.
It is really the only way to test out everything you think you might need.


Less is Better.

Roger that, as a matter of fact, as soon as the snow goes away (couple more weeks) I'm going to load her up and...from my house to a Sierras campground 76 miles away, Grover Hot Springs, do an overnight then back home again in morning. That way I can check out the rig on the road AND the camping equipment. If it all works out, it'll just be weekend centuries, mountain biking (just got a Cannondale Team Scalpel) Computrainer work....until departure day. I love this sport! My 3 motorcycles in the garage sure have taken a back seat recently. Raydog

vegenaise 03-07-10 02:07 PM


Originally Posted by kyakdiver (Post 10491860)
Why use a compact double and not a fixie weak sauce? Man up mediocrity.

once did a century on a brakeless loaded fixie with a collapsed lung. no manning up needed over here.

edit- oh and this applies for dewaday's comment as well.

kayakdiver 03-07-10 02:09 PM


Originally Posted by vegenaise (Post 10492788)
once did a century on a loaded fixie with a collapsed lung. no manning up needed over here.

I bow to you super power ability.:lol:

dewaday 03-07-10 04:01 PM


Originally Posted by vegenaise (Post 10492788)
once did a century on a brakeless loaded fixie with a collapsed lung. no manning up needed over here.

u needed a lung, pfffft!

LeeG 03-07-10 04:01 PM

I once rode half way down Hwy1 on mushrooms, it was downhill all the way.

vegenaise 03-07-10 07:41 PM


Originally Posted by dewaday (Post 10493149)
u needed a lung, pfffft!

yea, spontaneous pneumothorax can be a real *****.


Originally Posted by LeeG (Post 10493150)
I once rode half way down Hwy1 on mushrooms, it was downhill all the way.

were you afraid of crashing?

i was thinking the other day if it would be fun to ride while on mushrooms but every time i take mushrooms i get super exhausted and have to lay down and rest every 15 minutes. i don't think i could do it.


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