Big jockey wheels - good or bad?
Big jockey wheels - good or bad?
Apologies if this has been covered before.
Or (always possible with my goldfish mind) I have already started such a topic.
But are they good or bad?
Pros and cons?
Reason I ask is that although the "standard" size seems by far the most common, I have the idea that big jockey wheels are on SOME high end stuff and SOME cheap stuff.
Which seems kind of odd.
I appreciate that replacement is more straightforward with the standard size.
Or (always possible with my goldfish mind) I have already started such a topic.
But are they good or bad?
Pros and cons?
Reason I ask is that although the "standard" size seems by far the most common, I have the idea that big jockey wheels are on SOME high end stuff and SOME cheap stuff.
Which seems kind of odd.
I appreciate that replacement is more straightforward with the standard size.
Sweep
Re: Big jockey wheels - good or bad?
I's say technically better -
bigger jockey wheels will rotate with fewer rpm for a given cadence, so less wear and tear.
bigger jockey wheels mean more teeth (bigger circumference), so less wear and tear.
I think some claim quieter running also.
Debit
when running a cross chain, it can be easier for the chain to derail from the lower jockey wheel with bigger diameter at the point the chain joins it. When I see this though, it is usually on a worn and/or misaligned rear gear (typically Shimano Altus).
Visually I think they look far worse.
Some of the latest Campag stuff has big jockey wheels, one review said it looked like a cheap Shimano gear (bit of an insult when the mech probably costs way more than an entire cheap Shimano group set!). Must be progress for you.
bigger jockey wheels will rotate with fewer rpm for a given cadence, so less wear and tear.
bigger jockey wheels mean more teeth (bigger circumference), so less wear and tear.
I think some claim quieter running also.
Debit
when running a cross chain, it can be easier for the chain to derail from the lower jockey wheel with bigger diameter at the point the chain joins it. When I see this though, it is usually on a worn and/or misaligned rear gear (typically Shimano Altus).
Visually I think they look far worse.
Some of the latest Campag stuff has big jockey wheels, one review said it looked like a cheap Shimano gear (bit of an insult when the mech probably costs way more than an entire cheap Shimano group set!). Must be progress for you.
Re: Big jockey wheels - good or bad?
PT1029 wrote:Some of the latest Campag stuff has big jockey wheels, one review said it looked like a cheap Shimano gear (bit of an insult when the mech probably costs way more than an entire cheap Shimano group set!).
Yes - interesting - confirms my initial impression - but then so much in modern cycling is about fashion and creating the right impression.
Interested in more views of course on the technical merits and demerits.
In the meantime my 8 speed alivio rear mech is still rolling.
By the by (if my mech survives long enough to merit replacement jockeys) are all shimano "big" wheels effectively the same/compatible?
Sweep
Re: Big jockey wheels - good or bad?
Sweep wrote:
By the by (if my mech survives long enough to merit replacement jockeys) are all shimano "big" wheels effectively the same/compatible?
they vary in size, so you need to get ones that are close-ish else there may be problems. They also vary in quality.
Good points
- they are more efficient (and quieter-running)
- they increase the total capacity of the mech (BITD SunTour designed a mech with three pulleys, which had a lot of chain wrapped around them when the small-small combination was in use. Big pulleys achieve the same objective, but more simply.)
Bad points
- in any given mech they reduce the allowable maximum sprocket size (simply by reducing the reach of the mech)
- when you are shifting (for any given clearance in the pulley bushing) the 'slop' in the pulley is made larger whenever the pulley is increased in size.
- when you are shifting the twisting (wearing) load on the bushing is higher.
Thus the net effect is that bushings on large pulleys may inherently wear faster and be less tolerant to such wear.
There are also problems which are to do with execution rather than conception; in shimano mechs which have large pulleys
a) the pulley bushings are made very cheaply
b) the pulley bushings are sometimes lacking even the most basic dust shields
c) the rest of the mech that the pulleys are attached to is designed to wear out prematurely
That the chain seems to come off such pulleys more easily is a lot more to do with the fact that it is a cheap knackered mech than the size of those pulleys IMHO.
Overall if the mech is designed from the ground up to use large pulleys and is built with a high enough quality there may be more positives than negatives. Racers are not going to turn their noses up at another 1-2W for free.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Big jockey wheels - good or bad?
I think Shimano used 10t guide, 13t tension, as well as 10t/10t on previous models. They marketed 11t/11t as an improvement, and the 10t was relegated to Tourney, and eventually almost everything had 11t/11t. They would sometimes put out things like 13t/13t on various models, and at one point came out with 13t/15t Smart. They also called Dura Ace RD-7700 with two 13t wheels 'Smart', but it was back to 11t for 7800
Smart was on 2002's Altus CT95 & Acera M340, and continued as Altus M310 in 2007, but deleted the Smart Acera model was deleted. It also appeared on 2200, which was pre-Claris. 2300 was 11/13, which is also found on some other lower-end models.
Altus M310 continues to be sold alongside the latest 11t M3000 models
The lower end 13t models that are still sold are not very high-profile, and now they've put out 13t on all their new 12-speed MTB stuff.
This is (cheap) M310 smart with the 13t/15t
This is pricey RX810 which goes with a 48/31 chainset and has 13t
And this is still somewhat pricey RX400, which goes with a 46/30 chainset, and has 11t
And here again the 13t M8100
cf. M8000
SRAM Eagle uses 12t/14t btw
Both Eagle and the 12-speed Shimano are designed for enormous, heavy/expensive cassettes, 10-51t for Shimano and 10-50t for SRAM.
M8000 'only' went up to 11-46t.
Smart was on 2002's Altus CT95 & Acera M340, and continued as Altus M310 in 2007, but deleted the Smart Acera model was deleted. It also appeared on 2200, which was pre-Claris. 2300 was 11/13, which is also found on some other lower-end models.
Altus M310 continues to be sold alongside the latest 11t M3000 models
The lower end 13t models that are still sold are not very high-profile, and now they've put out 13t on all their new 12-speed MTB stuff.
This is (cheap) M310 smart with the 13t/15t
This is pricey RX810 which goes with a 48/31 chainset and has 13t
And this is still somewhat pricey RX400, which goes with a 46/30 chainset, and has 11t
And here again the 13t M8100
cf. M8000
SRAM Eagle uses 12t/14t btw
Both Eagle and the 12-speed Shimano are designed for enormous, heavy/expensive cassettes, 10-51t for Shimano and 10-50t for SRAM.
M8000 'only' went up to 11-46t.
Last edited by thelawnet on 21 Oct 2019, 6:51pm, edited 1 time in total.
Re: Big jockey wheels - good or bad?
going back a looong way, some versions of the shimano 'crane' RD were fitted with 9T pulleys. They were made from solid steel, and (provided they were lubed) were practically indestructible.
cheers
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Big jockey wheels - good or bad?
Brucey wrote:going back a looong way, some versions of the shimano 'crane' RD were fitted with 9T pulleys. They were made from solid steel, and (provided they were lubed) were practically indestructible.
cheers
I do like the sound of those.
Why did they disappear?
Shades of the Man in the White Suit?
Sweep
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Re: Big jockey wheels - good or bad?
Anything that increases the bend radius is good, from an engineering perspective. Paired with super slick, low friction bearings, they look an even better bet.
Re: Big jockey wheels - good or bad?
Sweep wrote:Brucey wrote:going back a looong way, some versions of the shimano 'crane' RD were fitted with 9T pulleys. They were made from solid steel, and (provided they were lubed) were practically indestructible.
cheers
I do like the sound of those.
Why did they disappear?
Shades of the Man in the White Suit?
This Crane model was the one that came with the first Dura-Ace groupset. The mech was designed to accept either 9T or 10T pulleys.
Longevity isn't everything though; the 9T steel pulleys were relatively heavy, noisy, inefficient etc. A good point was that they had an odd number of teeth, which meant that the teeth wore more evenly than with 10T pulleys. The bearings were just plain bushings though.
BITD Campagnolo used solid steel pulleys with adjustable ball bearings in them . They usually lasted very well indeed but there are problems; one is that if water gets into the bearing it is trapped there and doesn't drain away. Another is that these pulleys don't work well with modern chains, because in modern chains the side plates don't stand far proud of the rollers. This means that pulleys without fairly pronounced teeth just don't have any lateral traction, and the campag pulleys had no teeth, just serrations on something that was practically round otherwise.
Campagnolo steel pulley, from the days when the Gran Sport was a solid lump of steel and bronze.
IIRC the white suit was in fact flawed too; at the end of the film one is left wondering if an improved version might be possible.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Big jockey wheels - good or bad?
The man in the white suit film was flawed because simply having a material that would last forever would not have unduly affected output as people don't want the same thing forever. What did affect those workers was cheap clothing coming in from abroad.
Having an old bike with another fifty years left in it hasn't stopped people buying new offerings
I found in MTB plastic jockey wheels that the teeth and bearings wear out roughly together, larger diameter ball races would be better for wear and for seal life but manufacturers seem reluctant to do that, Probably because of perceived drag. Shimanos hardened steel bushings seem to be the simplest & most effective bearing at that size.
Having an old bike with another fifty years left in it hasn't stopped people buying new offerings
I found in MTB plastic jockey wheels that the teeth and bearings wear out roughly together, larger diameter ball races would be better for wear and for seal life but manufacturers seem reluctant to do that, Probably because of perceived drag. Shimanos hardened steel bushings seem to be the simplest & most effective bearing at that size.
Cheers
J Bro
J Bro
Re: Big jockey wheels - good or bad?
jb wrote:The man in the white suit film was flawed because simply having a material that would last forever would not have unduly affected output as people don't want the same thing forever....
That is far more true now than it was then, I feel.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Big jockey wheels - good or bad?
Brucey wrote:jb wrote:The man in the white suit film was flawed because simply having a material that would last forever would not have unduly affected output as people don't want the same thing forever....
That is far more true now than it was then, I feel.
cheers
Both comments very true.
Sweep
Re: Big jockey wheels - good or bad?
I'm quite glad my flared jeans didn't last forever.
Cheers
J Bro
J Bro