Geometry at sag

[flamshmizer]

Hoping to create a bit of a discussion here, wondering what everyones opinion is on static vs. dynamic geometry.

One example is the old (06-09) Glorys compared to the new ones. The new ones have the same static head angle, but lack 10% of the rear travel, which means at sag their head angles will be quite different. Same with the V10's, they're bottom brackets are quite high when you look at the numbers, but while under sag they're much more normal.

Should manufacturers state the geo under 25-30% sag more frequently? I have seen in at some places, but it doesn't seem to be common. I know there will never be a perfect system to compare bike geo given the number of different travel lengths getting around, but surely measuring at sag will give you a better idea than measuring geo while the bike is standing still.

What's everyones thoughts on this?

 

[driftking]

I think it is more ideal in terms of how the bike is going to ride, however it is a little difficult. The bike under zero rider load is always the same geometry so the there is a sort of standard to measure and compare bikes to. The issue Comes when sag will Vary from rider to rider, using geometrys of 25-40% sag is going to mean alot of Geo measurements or a big range stated which may not be hugely helpful. The manufacturer would also have to take into account fork sag as well, the amount of fork sag mixed with shock sag gives tonnes of combinations. Then there are a few shocks that require different sag than others so that throws another factor in,so although in theory it's a awesome idea and I'd like to see it, there are too Many factors to give accurate Geo numbers. They could give Geo based on the industry standard of 20-25% fork and 30-35% rear.

 

[flamshmizer]

Well thats the thing, as you said all those factors make dynamic geo hard to measure, but those same reasons make static geo next to useless. The V10 is my favourate example, 64/65 degree head angle sitting still but with all that rear suspension and less front suspension, its dynamic head angle must be slack as. I mean, 64 degrees on a V10 is not 64 degrees on a Specialized demo, and won't feel as such.

It gets worse once you start transfering over to AM bikes and the like. 66 degrees sounds pretty slack, but once you include the sag its head angle will be 3-4 degrees steeper than a 64 degree DH bike.

I suppose its just something you have to think about when purchasing a bike, and crunch the numbers for yourself. But I personally feel there is room for improvement here, especially how in the last few years people have become increasingly more obsessed with geo (with good reason). Thats why the angleset is doing so well.