bottom bracket / craknset quesation HELP!!!

On 9/3/05 4:27 pm, in article [email hidden],

mark potter said:

hi all

im about to buy a new crankset for my mountain bike

im gonna get a shimano alivio (mc20) for it, but I have 2 questions

1 - ive currently got a 68 x 110mm bottom bracket fitted is this gonna be
ok? (currently running 8 speed shimano setup)

Quite possibly. What are you replacing?

Quoted message said:

2 - ive got a choice of 175 and 170 crank lengths, I use 175 at the moment,
they have black in 175 and silver in 170 I want the silver one will I really
notice the difference in length ( I run a 170 on my road bike)

Depends if you spin or grind. If you spin then spinning will be easier with
the shorter cranks.

I have 162.5 on the MTB and 165 on the road bike (but I do have short legs).

...d

im replacing the original crank which was fitted (got a '03 barracuda XC400)
badged KRONOS but got "cyclone" on the back ??
"David Martin" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

On 9/3/05 4:27 pm, in article [email hidden],

mark potter said:

hi all

im about to buy a new crankset for my mountain bike

im gonna get a shimano alivio (mc20) for it, but I have 2 questions

1 - ive currently got a 68 x 110mm bottom bracket fitted is this gonna be
ok? (currently running 8 speed shimano setup)

Quite possibly. What are you replacing?

Quoted message said:

2 - ive got a choice of 175 and 170 crank lengths, I use 175 at the
moment,
they have black in 175 and silver in 170 I want the silver one will I
really
notice the difference in length ( I run a 170 on my road bike)

Depends if you spin or grind. If you spin then spinning will be easier
with
the shorter cranks.

I have 162.5 on the MTB and 165 on the road bike (but I do have short
legs).

..d

I got quite long legs, - 34" inside legs!! but then I run 170 on road bike?

mark potter said:

hi all

im about to buy a new crankset for my mountain bike

im gonna get a shimano alivio (mc20) for it, but I have 2 questions

1 - ive currently got a 68 x 110mm bottom bracket fitted is this gonna be
ok? (currently running 8 speed shimano setup)

ok, gives 47.5 mm chainline

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

On 9/3/05 4:40 pm, in article [email hidden],

mark potter said:

im replacing the original crank which was fitted (got a '03 barracuda XC400)
badged KRONOS but got "cyclone" on the back ??
"David Martin" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

On 9/3/05 4:27 pm, in article [email hidden],

mark potter said:

hi all

im about to buy a new crankset for my mountain bike

im gonna get a shimano alivio (mc20) for it, but I have 2 questions

1 - ive currently got a 68 x 110mm bottom bracket fitted is this gonna be
ok? (currently running 8 speed shimano setup)

Quite possibly. What are you replacing?

Quoted message said:

2 - ive got a choice of 175 and 170 crank lengths, I use 175 at the
moment,
they have black in 175 and silver in 170 I want the silver one will I
really
notice the difference in length ( I run a 170 on my road bike)

Depends if you spin or grind. If you spin then spinning will be easier
with
the shorter cranks.

I have 162.5 on the MTB and 165 on the road bike (but I do have short
legs).

..d

I got quite long legs, - 34" inside legs!! but then I run 170 on road bike?

Unless you really spin, go for the longer ones..

...d

mark potter said:

1 - ive currently got a 68 x 110mm bottom bracket fitted is this

gonna be

Quoted message said:

ok? (currently running 8 speed shimano setup)

The first number in the 68 x 110 designation is the width of the bottom
bracket shell, so make sure the new BB is also 68 width.

The second number is the spindle length, and the length required
depends on the chainset - probably best to ask wherever you are buying,
or look it up on the Shimano website.

d.

thanks dave but I kind of already realised that ( I had to measure it on the
bike to find out what it was)
"davek" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

mark potter said:

1 - ive currently got a 68 x 110mm bottom bracket fitted is this

gonna be

Quoted message said:

ok? (currently running 8 speed shimano setup)

The first number in the 68 x 110 designation is the width of the bottom
bracket shell, so make sure the new BB is also 68 width.

The second number is the spindle length, and the length required
depends on the chainset - probably best to ask wherever you are buying,
or look it up on the Shimano website.

d.

mark potter said:

thanks dave but I kind of already realised that ( I had to measure it

on the

Quoted message said:

bike to find out what it was)

Yeah, that's me misunderstanding the question again...

You want to know if the bottom bracket you've already got will be
compatible with the new chainset, right? Well, I'm no expert but I'd
guess that chances are if you are replacing like with like (say you are
replacing one Shimano triple chainset for another Shimano triple
chainset) you should be OK.

If you are replacing a double with a triple (or vice versa), or one
make for another (eg a TA for a Shimano), then you might need a BB with
a longer or shorter spindle. Or you might not...

Er... that's not very helpful, is it...

d.

"davek" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

You want to know if the bottom bracket you've already got will be
compatible with the new chainset, right? Well, I'm no expert but I'd
guess that chances are if you are replacing like with like (say you are
replacing one Shimano triple chainset for another Shimano triple
chainset) you should be OK.

I've just been caught by this - my old LX chainset doesn't match the cheaper
triple I cut off my wife's bike, so until I extract the rest of it she's got
no big ring. At least she's got a reliable middle ring now though...

cheers,
clive

On 10/3/05 1:30 pm, in article
[email hidden], "Clive George"

Quoted message said:

"davek" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

You want to know if the bottom bracket you've already got will be
compatible with the new chainset, right? Well, I'm no expert but I'd
guess that chances are if you are replacing like with like (say you are
replacing one Shimano triple chainset for another Shimano triple
chainset) you should be OK.

I've just been caught by this - my old LX chainset doesn't match the cheaper
triple I cut off my wife's bike, so until I extract the rest of it she's got
no big ring. At least she's got a reliable middle ring now though...

I found that.. tried to see if my new chainset (TA Carmina) would go on the
same BB as the old Ultegra one. No such luck, about 2mm too long to be able
to fettle it. At least that means that whoever decides to purchase my old
chainset will get the right length BB with it.

...d