freesafety22

hi guys,

i got some great help on upgrading wheelsets to a carbon version with a great deal from a UK vendor and am hoping for some help on the same bike. it is a ti javelin road bike with ultegra components and needs some parts.

i am told i need a 10 speed, 12 - 25 cassette and a 53 tooth 110 BCD chain ring (large).

i have a new chain but it is skipping on the fourth gear up on the cassette and the large chainring is "shark toothed" (the small chain ring seems fine and the rear derailleur will probably hold up).

right now i have found the ultegra cassette ($59) on performance cycles but they don't seem to have a compatible chain ring.

any advice on getting a good deal and is it possible to ask for URL's so i don't screw this up? for some reason i am thinking i might make a mistake with not getting the BCD correct or something.

thanks in advance,

jon

bradtx

freesafety22, Are you sure the chain ring is worn out, that would take a lot of miles. many have confused the sculpted teeth as being worn.

Look on ebay or other web stores for a 6600 or a 6700 chain ring... 6750 is a compact version that won't fit.

Brad

rm -rf

Yeah, your chainring might be worn excessively if you ran a very worn, elongated chain for a long time.

But modern chain rings have specific shaped tooth shapes that can look like wear. It's normal to see the same set of shapes repeating around the ring. The small chain ring has less extreme shaping, since the chain doesn't get pulled up to it, just off of it. (On my first modern bike, I had the same reaction after a few months, thinking the big ring was terribly worn.)

For example, here's an Ultegra crankset at 5000 miles, with very minimal wear. Just the black anodizing surface has been worn off. The chain is pulled counter clockwise in this view -- the back non-pulling sides of the teeth are more rounded to help with shifting.

HillRider

First you probably don't "need" a 12x25 10-speed cassette, it may just be what you have now. You can change your cassette range if you want different gearing and you don't have to use an Ultegra (6600 or 6700) cassette either. 105 or Tiagra 10-speed cassettes will work just as well and cost less. Dura Ace 10-speed cassettes will work well, be a bit lighter and cost WAY more.

Second, are you sure about that 53T, 110 BCD chainring? Ultegra 10-speed FC-6600 and FC-6700 standard cranks used a 130 mm BCD and were geared 53/39. Ultegra compact 10-speed cranks (FC-6750, etc) used a 110 mm BCD but came with 50/34 chainrings. Again, 105 chainrings with the proper BCD and tooth count will work equally well.

dsbrantjr

I would suggest changing out only your cassette first since you already have a new chain Only consider a new chain ring if the old one does not work with the new chain.

freesafety22

hi HR, all,

thanks a lot. took it to my LBC and they gave me the chainring measurements.

some questions please?

1. do i just count the teeth on the chain ring? where do i measure the diameter from? sounds like ultegra 6600/6700 should do it. is there a difference?

2. sounds like ultegra 6600/6700 will work as well for cassette? any differences?

3. 12x25 works for me i think. i never understood these well. i guess the ones in between are equally spaced out? is there a way to thing about alternatives? like i could get a 35x8 or something (?!) and gave an easier uphill gear and a "heavier" downhill gear?

THANKS

dksix

You'll find the model number of the inside of the drive side crank arm above the pedal hole. A 6700 will be 130 BCD and the 6750 will be 110 BCD, I'm pretty sure about that. It's hard to measure BCD which has an odd number of holes, you could find the hole to hole distance online but finding the part number will be best.

See picture

freesafety22

hi guys

again thanks for the help.

looks like it says "shimano SGX 53 b"?

how do these teeth look?!

THANKS

edit: looks like i need 10 points to post a url/link and i can't post images? how do i work thie please?

freesafety22

[QUOTE=dksix;19549616]You'll find the model number of the inside of the drive side crank arm above the pedal hole. A 6700 will be 130 BCD and the 6750 will be 110 BCD, I'm pretty sure about that. It's hard to measure BCD which has an odd number of holes, you could find the hole to hole distance online but finding the part number will be best.


THANKS man

it says 172.5 and f.c. 6600 a

would love to post a pic of the chainring but it sound like i need to order a cassette.

am i right to thing that if it SKIPS when i downshift to fourth gear on the cassette that the xasette teeth are worn? seems weird to me that steel cassette would be worn but not aluminum chainring, no?

THANKS again

<edit: jesus i can't even post a url in the reply without getting an error...>

freesafety22

[QUOTE=rm -rf;19541081]Yeah, your chainring might be worn excessively if you ran a very worn, elongated chain for a long time.

But modern chain rings have specific shaped tooth shapes that can look like wear. It's normal to see the same set of shapes repeating around the ring. The small chain ring has less extreme shaping, since the chain doesn't get pulled up to it, just off of it. (On my first modern bike, I had the same reaction after a few months, thinking the big ring was terribly worn.)

For example, here's an Ultegra crankset at 5000 miles, with very minimal wear. Just the black anodizing surface has been worn off. The chain is pulled counter clockwise in this view -- the back non-pulling sides of the teeth are more rounded to help with shifting. =QUOTE]

thanks LBS said they were "shark toothed". i guess if i can figure out a way to post a pic i can show them....

dksix

[QUOTE=freesafety22;19549656]I don't see how a worn cassette could cause it to skip cogs when down shifting. I would think that worn teeth would allow the chain to slip across the teeth and not propel the bike forward. The reason the steel cassette would be worn and not the aluminum chain ring is because the larger chain ring distributed the force over more teeth. A 50 tooth chain ring let the chain engage at least half the teeth all the time, that's 25 teeth holding the chain, a say 14 tooth cog is supporting that same force over just 7 teeth (probably less since the chain may not wrap the 180 degrees around that cog because of having to wrap the read derailleur).

I think that is why.

freesafety22

[QUOTE=dksix;19549689]got it. thanks

freesafety22

so looks like i need to order a

Ultegra FC 6600 A chain ring / Shimano SHX 53 B
and a
12 x 25 Ultegra 6600 chainring <edit: should read /cassette/>

does that sound about right?
unless i change out the cassette for more low end or top end power?!
THANKS

HillRider

The 12x25 is a cassette, not a chainring.

Get a larger large cog (say a 12x27 cassette) if you want more climbing help. A smaller small cog (11T instead of 12T) won't give you more power but it will offer more speed IF you are strong enough to turn it. Very few riders are.

freesafety22

hi HR

thanks a /lot/.
is there such a thing as an 11x27 - say if you wanted to transmit force while going down hill (instead of spinning) but also wanted some help in uphill?
THANK YOU

HillRider

I don't think there is an 11x27 but there is an 11x28 which is even better for climbing too.

Here is one source:https://www.amazon.com/Shimano-CS-67...-28&th=1&psc=1

And another:wiggle.com | Shimano Ultegra 6700 10 Speed Cassette | Cassettes And Freewheels

Racing Dan

Depending on desired ratio there is also the hg500 cassettes. A lot cheaper.

wiggle.com | Shimano CS-HG500 10 Speed Cassette (11-25/12-28) | Cassettes And Freewheels

and 105 5700

https://www.wiggle.com/shimano-105-57...peed-cassette/

HillRider

Yes, I knew about those but the OP seems to be stuck on Ultegra-level components so that's what i linked to.

rm -rf

(One more post, and you'll have 10 posts and can link those "shark fin" chainring photos.)

Flatland vs climbing drivetrains

These examples are 11 speed cassettes. (I now see you have 10-speed. The 12-25 in 10-speed skips the 18 tooth cog that's included in 11-speed. And there is a 12-28 in HG500, the same as a 11-28 in 11-speed but skipping the 11 tooth cog.)

These charts are from Mike Sherman's Gear Calculator. Here's the 50-34 and 12-28 example. You can click it's "Bookmark Gear Set" button, and save the URL for later recall. All the charts update on the fly as you change gears or cadences.

Your 53-39 crankset won't fit 50-34 chainrings, the chainring bolt hole circle is too big.

53-39 and 12-28
You have 39-53 chainrings and a 12-25 cassette. That's great for flat riding without steep hills, and for fast riding, like fast group rides or racing.

Here's your setup at typical road cadences, "spinning" instead of "mashing". The 53 chainring is in black, and the 39 is in red. There's very close shifts on the 53 chainring all the way from 15 up past 25 mph.

(I need close shifts in the low 20 mph range since I'm working very hard to hang with a fast-for-me group ride, and am trying for an efficient cadence.)

This is really nice for steady speeds on flatter rides, making it easy to find the the "just right" cadence, and it's great for all-out faster efforts. But hills will be difficult.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

50-34 and 11-28
Most bikes come with a "compact" drivetrain, which is 50-34 chainrings. And the 11-28 cassette is very common. (Some bikes are using 11-32 for even lower gears, but somewhat larger gaps in the middle.)

It's way easier on hills. But there's bigger gaps between gears at the faster speeds. Many riders would rather have the low gears for steep hills, and the gaps aren't a big problem for them.

Racing Dan

I figured as much. I just wanted to mention the other options because, IMO, they are just as good and alternative sprocket combinations are available than in the Ultegra lineup.

freesafety22

hi r,

thanks so much. i really can't believe i haven't educated myself about this earlier. very helpful info.

some quick basic questions please and then i'll link that image (thanks for the heads up).

i have 9 cogs in the cassette and obviously 2 chain rings. how do i know to call it a ten or eleven speed?
also, what does the "B" stand for on the chainring/crank? is this a shimano designation?

so given i don't have the compact chainring (actually curious as to what the smaller diameter (?) chainrings would do for me...) - i think i do need more help on the hills. i mean, i tend to be a masher and ride by myself. but i've noticed having help on the hills with this bike would be good. also, i do see the guys doing high cadences and i've gotten curious lately about this but it is probably another post.

am i looking for this cassette assuming i am not too worried about closely spaced gearing? i mean i LIKE having the ability to finely tune a ride when i am mashing up a hill or standing in the pedals but i think i would like more the ability to get out into some hills again (assuming i can stay with the routine and get acclimated to the weather again).

besides i can always switch back to a new version of what i have now (the 12 - 25 i think - with no B i guess?.

HG500[/B], the same as a 11-28

THANK YOU

HillRider

My comments are in red above.

freesafety22

OK. thanks a lot.

so looks like i need to settle on a 9 speed cassette and just buy it.
attached is the the chain ring. i can take more obviously.

THANKS

https://www.dropbox.com/s/gcldx6ved9abkt1/File%20Apr%2030%2C%208%2023%2007%20PM.jpeg?dl=0

freesafety22

sorry. i this is a 10 speed casette i think (10 cogs) i should probably look for a 9 speed or check my cogs again to see if i miscounted?

then 11 - 32 would give me more climbing ability (by some number of teeth) and a slightly smaller low gear (by dropping a tooth on the low gear)?

CS-HG500-10
Series SHIMANO
Number of Sprockets

11-12-13-14-15-17-19-21-23-25 //
12-13-14-15-17-19-21-23-25-28 //
11-12-14-16-18-20-22-25-28-32 //
11-13-15-17-19-21-23-26-30-34

Option 1 11-25T
Option 2 12-28T
Option 3 11-32T
Option 4 11-34T

HillRider

Please do. It would be nice to get the story straight. The difference between 9 and 10-speed cassettes is not trivial.