Bicycle Mechanics - Will one tooth make any difference?
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02-25-11, 01:29 PM
The 34/46-12-28 setup I've got on the Paramount PDG 3 needs 'just a tad' lower gearing to help these old legs.
the rx100 (and the 105 I have)simply won't work with a 30t cassette.
I really don't want to start messing with what I have. It works, I'm not climbing on every ride.
TA offers a ramped and pinned 33t.
The front derailleur (supposedly) will handle the 33/46 difference.
Just wondering how much 1 tooth drop will make.
Anyone have any experience with this?
I realize harris has an entire booklet of charts on gear ratios.
I was hoping for some seat of the pants feedback .
02-25-11, 01:35 PM
The change from 34T to 33T will lower your gearing by (1-33/34)*100 = 2.94% or about 3%. That isn't much and may indeed not be noticable to most riders. If you need a significantly lower gear, that won't do it.
+1 I don't think such a marginal improvement will change anything for you. If it's for rare hills bite the bullet and consider that even old legs can improve with conditioning.
If you're forced into an inadequate bottom gear often, don't work at the edges. Swallow your pride and go for a triple. This may involve some complications and expense, but can give you not only a lower bottom end, but much better selections in the mid range, and might make the whole bike better for you.
Yep. Not much change. Check out this graphical gearing calculator. I don't know if it'll help you decide but it's kind of cool. You can slide cogs and rings around to see the effect of different gearing and compare setups as well...
02-25-11, 02:44 PM
I'd get a MTB rear der (Deore XT is roughly 105 equivalent) and a 13-34 cassette. I did that for my wife's bike- it's an easy swap and it will give a 20% lower gear, which is significant.
I'm curious about which TA chainring you're considering. At the Peter White site http://www.peterwhitecycles.com/chainrings.asp the only 110 BCD 33t chainring I found is the Zephyr. A note says that the ring is not actually pinned but the "bolts" work as pins. I take this to mean that the chain is riding all the way down on the bolts. Or perhaps your BCD is smaller than 110 mm?
I think it may make more sense to try to adjust the rear derailleur to run with a 30t big cog on the cassette. A lot of people have reported good results with 30 and even 32 big cogs on their cassettes. You could try a longer "B" screw in the rear derailleur. Harris Cyclery (Sheldon Brown) offers cassettes with 30t cogs. You haven't said what your speeds are but you may be able to build your own cassette with a 30. A 13-30 cassette may be just what you need.
02-26-11, 01:12 AM
I've made this change myself. I never liked the normal compact crank with 34-50 rings because there were no cruising, mid-range gears, that didn't require me to cross-chain and/or double-shift frequently, and the low gears were not that low (compared to a triple crank that I'm more used to). However, I recently decided to upgrade my crank and decided to go with a compact to supplement my triple, and now I switch between them depending on the riding I'm doing. The compact crank came with 34-50 rings, but I almost immediately bought some Stronglight CT2 33 and 48 tooth rings.
Some people might think this small change wouldn't make a difference, but I'm obsessed with gear combinations, ratios, and cadence, and so I can tell the difference. A 3% difference in my cadence in the lowest gear is noticeable to me, and I appreciate having it. I also find that the 48 tooth big ring is better than the 50 tooth because it allows me to stay in the big ring longer without cross-chaining as much, and so I don't need to do the double-shift down to the inner ring as often.
BTW, I also use a 12-28 cassette. I prefer a higher cadence, and I was recently able to put power into the pedals and accelerate up to 75 kph (over 45 mph) with the 48-12 gear, so I certainly don't need any more than that. It helps that my cranks are shorter than average (167.5mm). The 12-28 has FAR better gear spacing than the 11-28 cassettes.
BTW, inner rings don't normally have or need any pins or ramps - the chain just drops onto and gets lifted off. Some might have "gates" built in to help the chain get off the ring, but these aren't even very necessary. Inner rings are pretty simple things. It's the outer rings where all the fancy stuff matters. I've used a lot of TA rings, but I do notice that they wear faster than stock Shimano rings. I've been happy with the Stronglight CT2 rings so far, but haven't put enough distance on them yet (maybe only 3,000 km) to test their durability.
Fortunately, I was able to sell my 34-50 SRAM Red rings to a friend who only had FSA Gossamer rings. You should be able to get something for your old 34 tooth ring if you stick it on e-Bay.
02-26-11, 02:09 AM
TA of France makes the 33t chain ring . the diameter is reduced ti wherether is not enough metal to make the counterbore to make the sleeve nut flush.
same thing if you get stainless steel 34 t the manufacturing uses no counterbore
because the material is not as thick as one would use if using aluminum
so the sleeve nut is not flush..
you need , in some cases to take the file to the end of your crank arm,spider
to make clearance for the smaller 33tring..
but a tooth or 2 on the wheel makes more difference..
Dude.. don't get attached to parts if the function no longer works for you.
it's a tool .. to get you places..
1 tooth on the cog on the hub makes a bigger difference..
02-26-11, 10:09 AM
TA of France makes the 33t chain ring.
He knows that. Read the OP.
02-26-11, 10:21 AM
He knows that. Read the OP.
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