Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 10-30-12, 09:31 AM   #1
frantik
Chainstay Brake Mafia
Thread Starter
 
Join Date: Mar 2011
Location: California
Bikes:
Posts: 5,974
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Making a custom cassette - few questions

Ok, I'm making a custom cassette.. are there any guidelines or theories I should follow?

I'm mostly making a custom cassette to build a 7 speed "straight block" out of various donor MTB cassettes to get closer gearing for the road

A few questions:

* Is there a maximum tooth size difference I should avoid? Like going from say, 18t to 28t is probably too much, but is there a guideline to follow?

* If I have something like 13-26 with a 53/39 up front, I should be able to run a short cage road RD, right? (specifically, Tricolor RD-7401)

* Does it matter if the spacers are different sizes (assuming friction shifting)?



as a general aside, I don't understand why more bikes don't come with straight blocks.. it seems like the gearing leaves a lot of overlap
frantik is offline   Reply With Quote
Old 10-30-12, 11:03 AM   #2
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 20,392
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 643 Post(s)
with older types of cassettes they come apart..
used 3 wee bolts to make assembly line simpler..

nowadays note the 'megarange'.. 24 and 34t are next to each other..


an IGH eliminates overlapping ratios.
fietsbob is online now   Reply With Quote
Old 10-30-12, 12:36 PM   #3
ThermionicScott 
Gratuitous glib and snark
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers)
Posts: 13,606
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 210 Post(s)
Quote:
Originally Posted by frantik View Post
Ok, I'm making a custom cassette.. are there any guidelines or theories I should follow?

I'm mostly making a custom cassette to build a 7 speed "straight block" out of various donor MTB cassettes to get closer gearing for the road

A few questions:

* Is there a maximum tooth size difference I should avoid? Like going from say, 18t to 28t is probably too much, but is there a guideline to follow?

* If I have something like 13-26 with a 53/39 up front, I should be able to run a short cage road RD, right? (specifically, Tricolor RD-7401)

* Does it matter if the spacers are different sizes (assuming friction shifting)?



as a general aside, I don't understand why more bikes don't come with straight blocks.. it seems like the gearing leaves a lot of overlap
Shimano still makes 13-14-15-17-19-21-24 and 13-15-17-19-21-23-26 cassettes. But you can't have a 13-26 straight block.

But yeah, you should be able to use the short cage, as you're only asking for 14+13=27 tooth capacity. And you're on the right track -- the spacers don't all have to be the same thickness for friction shifting, but you still need to make the cassette thickness correct in the end.
__________________
Quote:
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
RUSA #7498
ThermionicScott is offline   Reply With Quote
Old 10-30-12, 12:54 PM   #4
bobotech
Senior Member
 
Join Date: Jan 2012
Location: Spokane, WA
Bikes: Specialized Sequoia Elite/Motobecane Fantom Cross Team Ti/'85 Trek 520
Posts: 2,253
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
I would use same thickness spacers just for ease of assembly and consistency. What I do when I make a custom cassette is that I try to get the thickness of the gear and the spacer the same for all of the gears. For example, I will try to go for 4.8mm for gear/cog for 8 speed cassettes and so on. Even though you are friction shifting, it would be slightly annoying when shifting to have to move the lever a different amount for different gears. I just like consistency and knowing that if I move the lever a certain amount, it will shift.

PLus then you can use that same cassette with an indexed shifting bike.
bobotech is offline   Reply With Quote
Old 10-30-12, 12:59 PM   #5
frantik
Chainstay Brake Mafia
Thread Starter
 
Join Date: Mar 2011
Location: California
Bikes:
Posts: 5,974
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by ThermionicScott View Post
you can't have a 13-26 straight block.
straight...er block

i could buy one but that's not as much fun as making my own out of cassettes i have here. i will also be able to ensure i have it geared for my optimal range
frantik is offline   Reply With Quote
Old 10-30-12, 06:20 PM   #6
frantik
Chainstay Brake Mafia
Thread Starter
 
Join Date: Mar 2011
Location: California
Bikes:
Posts: 5,974
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
ok, i made a custom cassette, but looking at it, it doesn't seem like the hyperglide ramps are lined up correctly. the width of the teeth are also way different which makes me wonder just how well this cassette would shift

i swapped a hyperglide hub onto this wheel to improve shifting so I don't want to make it worse with a crazy cassette lol

13-14-15-16-17-18-26

frantik is offline   Reply With Quote
Old 10-30-12, 09:16 PM   #7
frantik
Chainstay Brake Mafia
Thread Starter
 
Join Date: Mar 2011
Location: California
Bikes:
Posts: 5,974
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
I had 3 cassettes I was using, and was trying to mix/match cogs from an 8speed and a 7speed cassette. I noticed the two 8speed cassettes were almost identical, so I guess the HG pattern changed at some point.

I just put the 7 speed back together and will just use it as-is, or buy a new cassette if i'm not happy
frantik is offline   Reply With Quote
Old 10-31-12, 12:02 AM   #8
ThermionicScott 
Gratuitous glib and snark
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers)
Posts: 13,606
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 210 Post(s)
That's interesting, a straight block plus bailout. Don't worry about the HG gates not lining up, it won't shift any worse than a pre-HG cassette.

As Sheldon noted, Shimano actually made several versions of most of the cogs concurrently, because the gates had to be in different spots depending on the cogs surrounding a particular one.
__________________
Quote:
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
RUSA #7498
ThermionicScott is offline   Reply With Quote
Old 10-31-12, 12:36 AM   #9
frantik
Chainstay Brake Mafia
Thread Starter
 
Join Date: Mar 2011
Location: California
Bikes:
Posts: 5,974
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by ThermionicScott View Post
That's interesting, a straight block plus bailout. Don't worry about the HG gates not lining up, it won't shift any worse than a pre-HG cassette.
This hub used to have a uniglide freehub body but I swapped it to hyperglide to get the advantage of improved shifting, so I would be moving backwards lol

the setup for 52/39 x 13-14-15-16-17-18-26 would be pretty good and given me 11 unique gears, vs the 9 i end up with on the stock cassette. I don't really get the point of having a front deraileur and extra chainrings to add only a tiny bit more range

maybe one day when I'm bored I'll try out the straight block with the mismatched gears and see how it shifts

Last edited by frantik; 10-31-12 at 12:41 AM.
frantik is offline   Reply With Quote
Old 10-31-12, 12:42 AM   #10
Sixty Fiver
Bicycle Repair Man !!!
 
Sixty Fiver's Avatar
 
Join Date: Sep 2007
Location: YEG
Bikes: See my sig...
Posts: 27,264
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Being able to make your own custom cassettes can be very enjoyable... theoretically speaking Shimano has single cassettes but no-one seems to be able to get them.

Back in the good old days, getting a custom freewheel or cassette was something every good shop was able to do and companies offered cog boards and cassette and freewheel bodies that could be built up for custom gearing or allow for cog replacements.

I have boards for just about every freewheel ever made and a Shimano board with UG cogs so have built up a good number of them from salvaged bodies and freehubs.
Sixty Fiver is offline   Reply With Quote
Old 10-31-12, 10:26 AM   #11
davidad
Senior Member
 
Join Date: Feb 2009
Bikes:
Posts: 4,896
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 24 Post(s)
Quote:
Originally Posted by frantik View Post
This hub used to have a uniglide freehub body but I swapped it to hyperglide to get the advantage of improved shifting, so I would be moving backwards lol

the setup for 52/39 x 13-14-15-16-17-18-26 would be pretty good and given me 11 unique gears, vs the 9 i end up with on the stock cassette. I don't really get the point of having a front deraileur and extra chainrings to add only a tiny bit more range

maybe one day when I'm bored I'll try out the straight block with the mismatched gears and see how it shifts
AS long as you are using friction shifting the ramps won't matter. In the days before indexing the cogs were cut square.
davidad is online now   Reply With Quote
Old 10-31-12, 10:41 AM   #12
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've tried integrating MTB cogs into a 7spd road cassette to make a 13-20, and IME the shifting where the HG doesn't match is worse than Uniglide; the cogs need to be designed to work together IMO.

As far as I'm concerned, HG and a straight block isn't going to happen until I can buy it, unfortunately
Kimmo is offline   Reply With Quote
Old 10-31-12, 04:23 PM   #13
frantik
Chainstay Brake Mafia
Thread Starter
 
Join Date: Mar 2011
Location: California
Bikes:
Posts: 5,974
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by Kimmo View Post
I've tried integrating MTB cogs into a 7spd road cassette to make a 13-20, and IME the shifting where the HG doesn't match is worse than Uniglide; the cogs need to be designed to work together IMO.
yeah i think the fact the teeth are aligned all funky would also make shifting worse.

Truthfully I'm not 100% satisfied with the shifting with the stock HG cassette.. I still get some slippage especially when going from 17 to 21t. This HG cassette and chain are from 1989, the first year HG came out so maybe the technology continued to improve. My diamondback with 1x7 drivetrain shifts buttery smooth and its got a super cheap thumb shifter and Shimano Altus RD! It does have a narrower chain though; I'm wondering if a newer 8speed chain would improve shifting.

Another option I'm thinking of is using one of the 8 speed cassettes and dropping the biggest cog. 39 x 11-12-14-16-18-21-(24 or 26) gives me a great range of useable gears. i wouldn't even need the 52t chainring. looks like i may end up with another 1x7 drivetrain
frantik is offline   Reply With Quote
Old 11-01-12, 06:15 PM   #14
frantik
Chainstay Brake Mafia
Thread Starter
 
Join Date: Mar 2011
Location: California
Bikes:
Posts: 5,974
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
well i guess i won't be doing the 11-26 cassette on this freehub body since the 11t requires a hyperglide-C (compact) body and the 7 speed freehub body i'm using is the old style. it's even got threading on the outside for compatibility with uniglide

do you have to start with the gear that has the "teeth" for the lockring? or can you use a larger gear? if it's best to use the small cog with the teeth for the lockring, the lowest cog i can start with is 13 i guess. i could also start with 14 if i used a uniglide lockring cog i have

Last edited by frantik; 11-01-12 at 06:27 PM.
frantik is offline   Reply With Quote
Old 11-02-12, 08:35 AM   #15
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There are at least a couple of quite good reasons why you don't want a small cog smaller than 13t anyway.
Kimmo is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:27 PM.