DH frame design

[Benj]

Long, low DH bikes look cool. do they ride better though?

'People' often talk about bikes with long wheel bases being great at speed because they are "more stable".
has anyone ever noticed speed wobbles (even on a BMX)?

Bikes look better with low shock placement. Do they really ride better? 'Everyone' loves to talk about a low center of gravity and how it makes the bike easier to throw around.
has anyone ever struggled to manouver a bike beause it had a high shock?

 

[kidafa]

my Duncon Cane Corso has a high shock but has a very low C.O.G. Having a high shock doesnt mean it has a higher COG. All the weight in my frame is around the BB area thur creating a very low cog making it sick for cornering...

 

[benji101]

Well all i have found out to do with this sorta stuff is that in corners i found from my old bike the stinky witch wasnt ver low to my new bike witch is alot lower when i was cornering it felt alot better felt faster and more force and that idea if that gives you an idea...

 

[I-AM-TEH-FASTEST-11]

yeh I like em low BB
short wheelbase (43) and steep head angles (66.5)

but maybe it's just the lack of sleep, stupid roadie k's and over caffination speaking

 

[---Matt---]

I don't really think there's enough mass in a bike to make the centre of gravity "that meaningful". Obviously every little bit counts when it comes down to it but I think when you add a rider of approx 85kgs to the equation, there isn't going to be that much effect of a few hundred grams located higher up the frame.

If you're worried about the centre of gravity, I'd focus much more on the BB height rather than the shock placement.

---Matt---

 

[t]

I think a lot of it is just asthetics, long low bikes look fast and more futureistic and tend to be more expensive too which might equate in many cases to being stiffer or lighter.I personally hate big rigs with a Kona style linkage, the shape is bulky and I think it looks cheap and old.

I sort of agree with Matt on low COG, that their is a lot of other factors that are more important to address first, like overly heavy rims or tyres for example they are unsprung and rotating mass. which will have way more impact on the cornering charectersistics of any bike than the COG.

After that comes basic geometry, chainstay length, wheel base, EFF TT lenngth, head angle, small changes in those measurements make huge differences.

Once you have got all those things sused then little things like wheel path, linkage design and COG. they can make a difference but not of the same caliber.