Offset rims

[Andy.M]

A question, why are my rims offset?

 

[apac]

so there is equal tension on both sides of the wheel? I'm not 100% but I think that the distance from the rim holes to the hub flanges differs on each side, so the rim offset equalises this difference.. thus making the tension on each side equal and therefore making the rim and wheel stronger? That's my guess.

 

[steve_sordy]

If the rim was not offset the spokes would hit the gears.

 

[Andy.M]

Ok, now I'm confused, I've never noticed this on any of my previous bikes.

 

[Gary]

Don't be confused. Just ignore Steve's post. It's nonsense..
Apac is correct.
No dish and even tension builds a stronger wheel. In order to achieve this with a modern cassette/Freehub rear wheel you require either offset dropouts, centralised equidistant hub flanges or an offset drilled rim.

 

[Andy.M]

Thats as clear as mud

I'll go with they look sexy !

 

[Kernow]

All very confusing answers
surely ,the answer a layman could understand is its because the gear cassette , or freehub requires more space than the brake disc the actual hub therefore sits off centre so the wheel has to be dished to allow the rim to run central in the bike frame ?

 

[Gary]

'spose it depends on the layman.
All replys so far except Steve's are correct.

 

[Kernow]

'spose it depends on the layman.
All replys so far except Steve's are correct.

Steve’s explanation although not technically correct kind of makes sense in a ŵay , makes me think he understands it anyway ?
Alan’s although correct , kind of missed the actual reason for the offset .
its A good one really , I think most people looking at the hub etc on the bike can see the reason. But actually describing it isnt so easy

 

[Gary]

There's no rear cassette hub and rim combination that would require the drive side spokes to be vertical enough to interfere with the rear mech,chain or largest cassette sprocket
you'd actually have to build the wheel with the rim way off centre (out of dish) towards the driveside stays. And by doing so it would also be loads weaker

The reason for manufacturers producing some rims with offset spoke eyelets is to achieve more even tensions between drive side and non driveside spokes. Not for gear clearance.

I'm not really sure how I could put it any easier understand without needlessly going into far too much detail.

 

[Kernow]

There's no rear cassette hub and rim combination that would require the drive side spokes to be vertical enough to interfere with the rear mech,chain or largest cassette sprocket
you'd actually have to build the wheel with the rim way off centre (out of dish) towards the driveside stays. And by doing so it would also be loads weaker

The reason for manufacturers producing some rims with offset spoke eyelets is to achieve more even tensions between drive side and non driveside spokes. Not for gear clearance.

I'm not really sure how I could put it any easier understand without needlessly going into far too much detail.

I think we’re actually trying to answer two different questions here , your literally answering the reason spoke holes in rim may be offset Which is what the question reallyinferred
I took the question to mean why is my rear wheel dished so the rim sits off centre of the hub Which I think is why Andy was confused by dime answers
Andy which was it ?

 

[apac]

A rim profile/cross section is not symmetrical.... it is 'offset'

 

[Gary]

Most aren't @apac

 

[Gary]

I covered both questions.
I don't think Andy was particularly interested in my answer to either. ?

 

[Rosemount]

I wrecked a rim .
Came home got out a wheel I bought 2nd hand, counted and measured the spokes .Using the Ben Cathro approved method .I then transferred the spokes from the rim with the dent to the new rim , one at a time . Raised the tension and trued the wheel .
When I remounted it in my bike it seemed misaligned ! Too close to the chain stay on the non drive side . Oh well time to test my work . Tyre would rub the chain stay when accelerating . WHaaa ? Then light bulb moment !! I remembered dishing ... Went back and watched Calvin from Park Tools explain rear wheel building .
So a cpl of turns on each spoke to tighten on the non drive side and a cpl to loosen on the drive side I managed to dish the wheel . Worked fine .

 

[urastus]

All very confusing answers
surely ,the answer a layman could understand is its because the gear cassette , or freehub requires more space than the brake disc the actual hub therefore sits off centre so the wheel has to be dished to allow the rim to run central in the bike frame ?

I'm not sure you achieved less confusion, but maybe added to it?

Maybe start with "what is the strongest spoked wheel"? One that is symmetrical where each spoke is sharing the same force. Remember the era of rim brakes? The front wheel was strongest if it was correctly made because it was symmetrical. Spokes on both sides of the wheel were equal length, and if it was a well made wheel, each spoke had close to equal tension.

Now consider a wheel with a disk brake or cluster. The spokes on the rotor or cluster side are shorter and have more spoke tension (the spoke nut is tighter) than the longer spokes on the opposing side. They are also more inline with the load placed on the wheel. Essentially you have half of the wheel spokes supporting most of the vertical weight and vertical forces to the wheel.

 

[Andy.M]

Wished I’d never asked?
After my first ride on my new to me focus I was hosing it down and noticed the spokes were on one side of the rim, never seen that before so thought I’d ask the experts!

just like asking what’s wrong with apple on an android forum. ?

 

[Gary]

Only if you struggle with reading.

 

[Kernow]

I'm not sure you achieved less confusion, but maybe added to it?

Maybe start with "what is the strongest spoked wheel"? One that is symmetrical where each spoke is sharing the same force. Remember the era of rim brakes? The front wheel was strongest if it was correctly made because it was symmetrical. Spokes on both sides of the wheel were equal length, and if it was a well made wheel, each spoke had close to equal tension.

Now consider a wheel with a disk brake or cluster. The spokes on the rotor or cluster side are shorter and have more spoke tension (the spoke nut is tighter) than the longer spokes on the opposing side. They are also more inline with the load placed on the wheel. Essentially you have half of the wheel spokes supporting most of the vertical weight and vertical forces to the wheel.

And I added to it ? so let’s start with another question .
this would interesting on an engineering exam paper . some mechanically minded people understand it just by looking at the rear wheel, it just an obvious solution to us , but actually explaining that to the person who doesn’t in words alone is a greater skill we all struggle with . The answers made sence to us who knew but not Andy So as teachers we all failed Sorry Andy ?

 

[Gary]

TBF I'm actually qualified to teach and assess cycle mechanic courses at further education level and have taught this stuff to far less mechanically minded people than we have here. I have to admit I do put a little more effort into delivering a course to paying students with an actual desire to learn than to an online stranger who's happy to ask questions and run away from the answers.

 

[Gary]

Read this Kernow.

It'll teach you far more than you ever wanted to know about bicycle wheels

 

[Jimbo Vills]

And I added to it ? so let’s start with another question .
this would interesting on an engineering exam paper . some mechanically minded people understand it just by looking at the rear wheel, it just an obvious solution to us , but actually explaining that to the person who doesn’t in words alone is a greater skill we all struggle with . The answers made sence to us who knew but not Andy So as teachers we all failed Sorry Andy ?

I must admit being fairly new to bicycle tech and jargon, it got me thinking.

So I had a little look online as I find visually sometimes can make something so much more simple.

This popped up and pretty much explained what I was thinking in my head in regards to the free hub and off set rims to achieve strength.

Well i think it makes sense now so i'll take that

 

[Zimmerframe]

Read this Kernow.

It'll teach you far more than you ever wanted to know about bicycle wheels

Does it have pop up's ?

 

[Zimmerframe]

No pop ups ... me no read ! ...

Do you think @BAMBAMODA has a pop up coffee table target book ??

Turn the page - new targets pop up , shoot the crap out of them (and maybe the tv if it's behind...) ..

 

[Zimmerframe]

Spokes are too complicated .. we need to simplify

 

[Gary]

I must admit being fairly new to bicycle tech and jargon, it got me thinking.

So I had a little look online as I find visually sometimes can make something so much more simple.

This popped up and pretty much explained what I was thinking in my head in regards to the free hub and off set rims to achieve strength.

View attachment 51481

Well i think it makes sense now so i'll take that

Google's quite good isn't it?
I dream of the day all internet forum users have access to it

The pic you've posted is just a marketing ad. and despite their claim Nox Composites still haven't managed to equalise flange distances or bracing angles.
If manufacturers actually cared about wheel strength/stiffness we'd all be running symetrical equidistant hub flanges and non offset rims that achieved genuine eqalisation in tensions and bracing angles. Which BTW is easily possible with boost 148mm, DH 150mm or superboost 157mm spacing hubs if someone would simply slim down the freehub body length by just 12mm leaving just enough space for a 7 or 8 sprocket cassette (depending on spacing).
#DisShitAintRocketScience

 

[Rosemount]

redacted .

 

[steve_sordy]

Don't be confused. Just ignore Steve's post. It's nonsense..
Apac is correct.
No dish and even tension builds a stronger wheel. In order to achieve this with a modern cassette/Freehub rear wheel you require either offset dropouts, centralised equidistant hub flanges or an offset drilled rim.

Wasn't @Andy.M talking about offset drilled rims?

 

[Gary]

Yes. I believe he was Steve. Doesn't make your reply any less nonsensical

 

[apac]

Read this Kernow.

It'll teach you far more than you ever wanted to know about bicycle wheels

Mastermind...
Name: Gary
Occupation: Anorak
Specialist subject: the bicycle wheel