[jeremy_2640]

Hi Everyone,

A friend and myself are design and manufacturing a DH bike frame for our final year uni. project. We are currently looking at customer requirements, we want constructive opinions (i.e. not - this frame is awesome!!!!! and crap like that) from people who meet this criteria:

- More than 2 years riding experience
- Have raced/ridden competitively
- Older than 16 years old

Here are the questions, if you could take some time to answer each question to the best of your ability we would be really happy - and remember this is your chance to influence a brand new DH bike!

What do you like about existing products (DH frames)?

What do you dislike about existing products (DH frames)?

What are the most important issues you consider when purchasing a DH bike frame/bike (not considering componentry)?

What improvements would you make to the products?

And finally and most importantly...

What specific features/atttributes and characterisitics do you desire in a DH race bike frame?

I need these answers by next Monday 25th, but feel free to continue suggesting idea's after that as we could include any important things initially missed.

Cheers
Jeremy

 

[UncaJohn]

Well, Ok,
What do you like about existing products (DH frames)?
-The DH race frames became a different breed of the FR frames (yep, ridding at a Dh cource is not the same as ridding up & down into trails/ramps & "hairy" ground.
- i do like the different "schools" on suspension design. After all from all these ideas new inovations will arrise.
What do you dislike about existing products (DH frames)?
-Way too expensive (well most of them) especially if you consider that racing involves some crashing too!
-Some are actually fragile.
What are the most important issues you consider when purchasing a DH bike frame/bike (not considering componentry)?
-well, a race bike owe to offer at the rider or mechanic the possibitity to play with the geometry and general set up. -I would like to see some reliable engineering.

UncaJohn

 

[matsO]

My contribution, FWIW, in orange

What do you like about existing products (DH frames)?
Morewood izimu – like the low weight, how it handles in the air, it has simple geometry adjustment by changing the shock mount in the frame. 64-65 head tube angle, normal chain stay length.
Turner DHR – like how it rails corners, stable, not as good balance as the izimu in the air (my experience). The frame has lower COG and longer wheelbase/chain stays than the izimu.

What are the most important issues you consider when purchasing a DH bike frame/bike (not considering componentry)?
Head tube angle, chain stay length, wheelbase, BB-height, complexity of suspension system, weight.

And finally and most importantly...

What specific features/attributes and characteristics do you desire in a DH race bike frame?
Proven compatibility with current standards, i.e. being able to fit chain guides etc without having to make adjustments.
Simple user-friendly constructions using standard parts (bearings…) you can find in local hardware store.
Light.

 

[ridefast]

nope, this type of thread has never been done before

really, it hasnt



try the search function?

 

[matsO]

Ok. there are other threads for you.

 

[Bikerpunk241]

What do you like about existing products (DH frames)? The fact that geometries are evolving, making the bikes more stable at high speed but also retaining their agility. Dropping overall bike weights while still increasing strength.

What do you dislike about existing products (DH frames)? Derailleur hangers and the pivots are the weak points. Sealed bearings are a huge improvement over bushing technology, but a lot of the time, companies use bearings that are much to small and wind up blowing out within a couple months. And then der hangers, unavoidable right now, always bent.....

What are the most important issues you consider when purchasing a DH bike frame/bike (not considering componentry)? First and foremost is the geometry. I won't even look at a frame if the head angle is to steep, followed closely by the TT and BB height. Beyond that, it doesn't really matter, a rider can pretty much over come anything.

What improvements would you make to the products? Larger bearings in the pivots, just so they won't blow out as fast, and gear boxes would be nice too, even if it is just a der in a box......


What specific features/atttributes and characterisitics do you desire in a DH race bike frame? I look for 8" travel, not steeper than 65deg head angle, a tt of at least 22.5" and a bb height of no more that 14.25". I really like high speed stuff, so a bike that will be stable at speed is a must, but it must also be laterally stiff, which I guess goes hand in hand with stability.

 

[demo 9]

Well, Ok,
What do you like about existing products (DH frames)?
-geometry, warrentys(sometimes), quality(usually)
i like my 303 its long, low, and slack. commencal has the right idea too.
most frames use same standards, tire clearance.





What do you dislike about existing products (DH frames)?
-standover(i dont sit) so it would be nice to have a dirt jumping bike standover height-let the bike ride higher up in rocks and stuff-u get more leg suspension
-weight?some frames are heavy but others are too light-LETS NOT MAKE A SOCOM
-PRICE!!!!
-wheel path, everybody has *basically* the same one, just a different way to get it



What are the most important issues you consider when purchasing a DH bike frame/bike (not considering componentry)?-geometry and wheel path
personally i look for a 64 HA, 14" or lower BB height
REARWARD ARCH-*hint* *hint* canfield

i would really like to see a gearbox bike with a BIG rearward arch

everything has its ups and downs so find a balance adjustable geo is a really nice thing to try to incorporate if possible

EDIT-im east coast

 

[zedro]

well I don't/haven't raced, but I've designed and built my own DH rig for my final year Uni project (years ago now), so here's my advice to you (sorry if it's off your topics, my attention span is too short anywho..):

-Look at the different designs out there, understand what they basically do/achieve/compromise....don't get caught up in peoples cheerleading camps (faux bars- 4 bars, dws, vpps, rah rah rah...) just pick a/some concepts you like and run with those...but be flexible, you can't have it all either.

-Don't try to make a Universal machine; variable geo, suspension rates, dayglo color patterns just complicate the design unnecessarily and create alot of compromises just to make the whole thing minimally work. Instead zero in your geo, have very limited adjustments if any, keep it simple, refine.

-Nobody can agree on geo or suspension types, but most people can differ between uber-clean design and clunky mud-grinders that take an hour to change the rear shock springs and a 4 lbs hammer to remove the rear axle. Just looking at the Canfield Bros Formula Jedi before, this rig exemplifies a very clean design (looks, structure, mechanics) despite packing in some more complex design features....but they have been refining this over a decade now, which leaves the last point:

-what is your overall design intent; this is what no survey will give you the answer to. Some customers want super-light super simple no frills ball busters, others want super-techy monsters that feel like they're riding their couch point and shoot style down the hill. And to this, what can you/want to achieve in your budget, time frame, and the fact that prototypes usually end up having 10 to 100% suckage factors depending on the design risks you took.

Sorry to ramble, haven't posted in like 2 years....oh yeah and good luck

heres my bag of bolts, not intended for production, or to be loved by 45% of the population...

 

[dump]

wow, zedro. talk about blast from the past. Pictures of that frame used to grace the pages of ridemonkey regularly.

 

[jeremy_2640]

Thanks for your posts guys, and yeah I could have done a search but then I wouldn't have got answers specifically for those questions (which I need) from the same person, that said....

Thanks for your input zedro it won't be a do it all bike, we have a very clean design envisioned. Your bike is a bit of a beast hahah!!! Does it come in under the 50kg mark?

Cheers

 

[jeremy_2640]

Double post...

 

[MobileChernobyl]

Make sure its looks flexy and comes in rootbeer and I'd say you have a winner no questions asked.