Adjustable Frame Geometry.

[Mikerb]

Quite a few bikes are now supplied with flip chips which is marketed as providing the opportunity to tune the same bike for different riding scenarios. But do they achieve that???
Some seem to consist of merely lifting or lowering the back end of the bike. Yes that certainly alters the bb height but then so does running different rear shock sag or different volume/profile rear tyre. The lower setting is said to slacken the head angle but both the head tube angle and front centre length is fixed (unless elliptical headset cups are fitted). The whole point of a slacker head angle is to push the front wheel further away from the centre of mass of the bike and that is dictated by the position of the bb with the riders weight centred over it. Merely making the bike sit down more at the back does of course change the angle of the headtube but does not change the front centre so are the claims misleading......or have I got it wrong!!

 

[The EMF]

That’s a good point, to me it’s all a bit too scientific for me. When I compare riding my old Raleigh Amazon (bike-not musclebound super chic) to my Whyte e150 there is a distinct difference. All the rest in between is gobble-de-gook and a bit of a blurr to me.

 

[Mteam]

Quite a few bikes are now supplied with flip chips which is marketed as providing the opportunity to tune the same bike for different riding scenarios. But do they achieve that???
Some seem to consist of merely lifting or lowering the back end of the bike. Yes that certainly alters the bb height but then so does running different rear shock sag or different volume/profile rear tyre. The lower setting is said to slacken the head angle but both the head tube angle and front centre length is fixed (unless elliptical headset cups are fitted). The whole point of a slacker head angle is to push the front wheel further away from the centre of mass of the bike and that is dictated by the position of the bb with the riders weight centred over it. Merely making the bike sit down more at the back does of course change the angle of the headtube but does not change the front centre so are the claims misleading......or have I got it wrong!!

You've got it a little bit wrong, which exact geometry measurements change and by how much and in which direction will vary depending on whether you alter a flip chip on the rear sus linkage, use a lower profile tyre, use angle adjusting headcups , use less air pressure in the shock etc.

A flip chip that lowers the bb, will also slacken the head angle, the seat angle, alter the reach, front centre, chainstay length etc, all by varying amounts.

An angle set will slacken the head angle, but steepen the seat angle,usually lengthen the reach, front centre, usually shorten chainstay length (but could lengthen it on certain bikes) , lower the BB , etc.

less air pressure in the shock will be similar to a flip chip, but will also affect how much the bike wallows, bottoming out more etc

Some differences in geo are so minor they're not worth mentioning - and you probably cant feel any difference,

I like this website for calculating differences in geo

geometryCalc (muha.cc)

 

[Mikerb]

You've got it a little bit wrong, which exact geometry measurements change and by how much and in which direction will vary depending on whether you alter a flip chip on the rear sus linkage, use a lower profile tyre, use angle adjusting headcups , use less air pressure in the shock etc.

A flip chip that lowers the bb, will also slacken the head angle, the seat angle, alter the reach, front centre, chainstay length etc, all by varying amounts.

An angle set will slacken the head angle, but steepen the seat angle,usually lengthen the reach, front centre, usually shorten chainstay length (but could lengthen it on certain bikes) , lower the BB , etc.

less air pressure in the shock will be similar to a flip chip, but will also affect how much the bike wallows, bottoming out more etc

Some differences in geo are so minor they're not worth mentioning - and you probably cant feel any difference,

I like this website for calculating differences in geo

geometryCalc (muha.cc)

As far as I can see the front centre remain the same. A chip that lower the BB does so at the same angle as the seat tube so that as the front wheel moves forward ( head angle slackens) the BB moves forward slightly and down and the front centre remains the same. If the front centre remains the same the head tube may well be slacker but the front wheel is no further foward of the centre of mass than it was before so the known characteristics of a slacker head angle ( slower but more centred and directional steering ) are not fully realized. Elliptical headset cups change the head angle and therefore extend the front centre..........BUT that also lowers the front of the bike and that alters the riders weight distribution on the bike unless cockpit changes a re made to compensate. So for me a flip chip on its own or a set of elliptical headset cups on their own can do more to disrupt rider weight distribution and cockpit design that they are worth. Maybe the gen3 Levo is slightly different in having both.........even so i think changes to the flip chip need to be done in association with change in the headset cups.
Still seems to me most are better off getting a bike with an appropriate geo for their type of riding in the first place!!

 

[Clubby]

Yup, it’s all a load of bollocks.
For me the issue is there’s not enough difference between the settings. A change of tyre size could make the same amount of difference. On the other hand if there was a bigger difference I’m pretty sure there would be one noticeably better than the other, rendering the other pointless.
Most reviews I’ve read say they’ve stuck it in the lowest/slackest and just left it there.

 

[Mikerb]

Yup, it’s all a load of bollocks.
For me the issue is there’s not enough difference between the settings. A change of tyre size could make the same amount of difference. On the other hand if there was a bigger difference I’m pretty sure there would be one noticeably better than the other, rendering the other pointless.
Most reviews I’ve read say they’ve stuck it in the lowest/slackest and just left it there.

...or whatever geo the bike was originally designed around?