Author Topic: Let's talk Geo - overall..custom advice  (Read 2736 times)

Offline The Brown Sound

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Let's talk Geo - overall..custom advice
« on: November 26, 2009, 06:06:31 PM »
So I am def wanting a custom twin tube frame. Yes some may say its excessive or pointless but it's what I grew up with. That said, I am rocking a Quamen Delta 4 that by far is the best fit for me. I was speaking w Malo a ways back about getting a custom twinner made. Below is a pic of the frame in question. I wanted the TT to come in a bit more like a my D4. a lil higher on the intersect. Malo made the comment in general the frame may be weaker due to this (if memory serves me correct) If the basic Geo is a diamond design (no bendies) would it be as strong as a normal diamond frame, or is it because the angles of the triangles are smaller, the overall strength is affected?

The other question is, how do I figure what TT length works for me, what CS works etc. HT I seem to like the 74.5 - not too twitchy up front. The back end I can't comment on as I'm not yet doing a lot of backyard tricks, though on peg wheelies it feels pretty good. I see a lot of people comment on a CS should be at least 13 for stability purposes. Obviously this is all subjective, but in the realm of custom frames, I want a frame I can grow with. That will suit my riding style as I progress. Cause I plan on hitting it like a mf'er. and progressing. Or should I not worry so much, and realize my opinion will also grow through experience and take it for what it's worth. I have this idea I will feel more comfy on a twin TT. I'm pretty used to the single TT Quamen, but have had to adjust. I can't tell how much of that is due to the shorter TT as I grew up on a Master/Ozone - and i believe those were in the 19" realm. For the record I am 5'8. Thoughts?

R. //

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Offline Jason

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Re: Let's talk Geo - overall..custom advice
« Reply #1 on: November 26, 2009, 06:27:16 PM »
I know that the twin top tube 1st gen Palmeros had breakage issues for Viki Gomez, which is why the later models had a larger flattened top tube.  I'm not exactly sure where the breaks came but this is what I was told by Pete B.

As far a geometry goes, I think that taking it for what it is would be the best route to take because your opinions will change with progression until you truly discover your ability. By all means do get a custom frame if you can because you will learn from that 10 fold.
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byke

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Re: Let's talk Geo - overall..custom advice
« Reply #2 on: November 26, 2009, 06:38:58 PM »
Geometry is completely different to each person so it can be hard to advise anyone.
The biggest problem with custom designed frames is that the information regarding how to design a frame is completely off.

The absolute first thing you need to figure out is how high you want your BB (normally 28mm to 48mm from the central axis line)

After that you need to figure out how long you want your front end and not by TT length but from the center of BB to front axle.

Thirdly you then need to figure out how long you want your CS from BB to middle of the dropout.


These are the 3 main factors ..... all the other bits are just detailing as such.
Personally from what I have read in regards to your above post I would recommend you get a big piece of paper and draw a frame and fork to scale and do a few more for a couple more weeks as I think you will find that you will want to change your mind a few times as you become more common to how frames work and the information sinks in.

I wish my imac was working properly as I would have made a small video otherwise to show how to draw and design a frame.

Offline letsgo

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Re: Let's talk Geo - overall..custom advice
« Reply #3 on: November 26, 2009, 07:10:54 PM »
byke is dead on.  Each aspect of geometry will produce various effects.  A low BB is more stable but too low will interfere with Stick-b tricks and make the front end seam heavy and an example..  If you just focus on the TT length slacking out the HT angle will add to the overall wheel base.  Generally a shorter wheelbase will help with both front wheel tricks and back wheel tricks.

However it all comes down to what you like.  Also as your riding evolves your geometry preferences will change.  Riders today run very different set ups than even two years ago.  But the tricks that are "in"  are turbine tricks (i.e. steamrollers) so you see wider bars and skinny tires.

For the long haul neutral geometry may serve you well.  Just gotta dance with who you came with.  I have  a 2002 G4 Quamen American BB, 76.5 HT angle, 18.75 TT and 1.85 tires.  Runs and a lot of riders come back to that geometry in our group.  In the end you can learn anything on anything.

Offline The Brown Sound

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Re: Let's talk Geo - overall..custom advice
« Reply #4 on: November 26, 2009, 08:28:14 PM »
Thx Byke and Jason. I'm on my phone so it's hard to reference the previous posts.

So BB height, what's a decent height btwn stable and a lil twitchy and out of the way. What's m quamen d4's bb height? And finally what stability does bb height affect?

Wheelbase - which I assume is mid bb to front hub. Shorter is good for back and front wheel tricks. Again what's a decent length and how do different lengths affect tricks/rideability.

Finall cs - is that mid bb to mid rear drop out? I like how my d4's cs I think though
when I tried backyards it seemed like it could of been a lil twitchy. Of course I'm not well versed in this trick and w peg wheelies it feels ok. Again I don't know any better lol thx for all the information guys!
I'm like the brown LL Cool J.

byke

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Re: Let's talk Geo - overall..custom advice
« Reply #5 on: November 26, 2009, 08:46:41 PM »
Quote
So BB height, what's a decent height btwn stable and a lil twitchy and out of the way. What's m quamen d4's bb height? And finally what stability does bb height affect?

If you go with 34mm you should be happy as its in the middle.
Many weight weenie companies are pushing up the bb's higher to help eliminate tubing and thus reduce weight. However this pushes the center of gravity higher and this "feeling" is to each their own. I personally like loooow BB's and am even having a frame buile at present with a 0mm bb height to se how it will feel having the cranks at the same height as the pegs.

Quote
Wheelbase - which I assume is mid bb to front hub. Shorter is good for back and front wheel tricks. Again what's a decent length and how do different lengths affect tricks/rideability.
Wheelbase is rear axle nut to front axle nut. I cant say whats good for you but if you measure your bikes that you like you will get a god understanding.

Quote
Finall cs - is that mid bb to mid rear drop out? I like how my d4's cs I think though
when I tried backyards it seemed like it could of been a lil twitchy. Of course I'm not well versed in this trick and w peg wheelies it feels ok. Again I don't know any better lol thx for all the information guys!

CS = chainstays / a rough term to describe the length from the rear axle nut to the center of the BB.


Again, measure the bikes you like, and then draw, draw , draw :)
« Last Edit: November 26, 2009, 10:24:35 PM by byke »

Offline Paradoxium

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Re: Let's talk Geo - overall..custom advice
« Reply #6 on: November 26, 2009, 10:11:56 PM »
Custom frames are for riders who aren't beginners, who have tried out many frames and know exactly what they want from each frame, and already know which geometries work for them for their tricks. That is why they get a custom frame.

If you go ahead with it, some extra suggestions from whats already been posted is if you don't know what cs length you prefer, you could go for 1 1/2" of travel instead of 1".
For example 12.5" - 14". Then you are sure to find the right length later on.

The 74.5 hta is spot on. Its what many experienced riders recommend as the best for front and rear wheel tricks, and is the middle of all the average ht angles.

There is so much more you need to work out before starting too, like sta, tt length, bb height, cs length, hta and so on.  However, you will get accustomed to any frame. ;)

Offline out~riding

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Re: Let's talk Geo - overall..custom advice
« Reply #7 on: November 26, 2009, 11:03:30 PM »
If you go ahead with it, some extra suggestions from whats already been posted is if you don't know what cs length you prefer, you could go for 1 1/2" of travel instead of 1".
For example 12.5" - 14". Then you are sure to find the right length later on.



I was going to say this also. Since you dont know what CS is better for you, keep your options by making the dropout slot longer. That way you can change, try different positions and finally find the perfect spot.

Offline hateit

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Re: Let's talk Geo - overall..custom advice
« Reply #8 on: November 26, 2009, 11:05:28 PM »
If you're asking on the board what should I get, than going custom probably isn't your best bet unless you  really can afford it . Geometry etc. is really such a personal thing. do you like shorter, longer ?, steeper, shallower?. You might be better off  getting some second hand frames to see what you prefer. asking, well does a short chainstay do this or that, people will probably give you completely different answers.

Offline The Brown Sound

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Re: Let's talk Geo - overall..custom advice
« Reply #9 on: November 27, 2009, 12:02:05 AM »
Hey guys - again thx for all the advice. I def appreciate customs being more for experienced riders who KNOW what they want. In a roundabout way I do know what I want, but by feel vs technical specifics. I've had the Metro and it felt awkward to me. But the D4 is perfect. Prob just get a twin tt version of it. Money isn't soooo much of an issue, cause I don't eat thru parts yet s $500 on a frame once every year or 2 isn't horrible. Really my D4 works best. Just want a twin tt - set and forget - then just focus on the skills, naww mean? Thx dudes!
I'm like the brown LL Cool J.

byke

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Re: Let's talk Geo - overall..custom advice
« Reply #10 on: November 27, 2009, 09:21:12 AM »
I was going to suggest you simply send your frame in for customization instead if you already have a frame you like, but want double toptubes.


Offline laughingmonkey

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Re: Let's talk Geo - overall..custom advice
« Reply #11 on: November 27, 2009, 12:33:50 PM »
hey byke, where'd you learn about frame design?
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byke

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Re: Let's talk Geo - overall..custom advice
« Reply #12 on: November 27, 2009, 12:39:49 PM »
Trial and error and working within the industry.

Offline The Brown Sound

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Re: Let's talk Geo - overall..custom advice
« Reply #13 on: November 27, 2009, 12:46:32 PM »
Byke, didn't you have a hand in designing the Mike S bars and other products widely used in flat?
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byke

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Re: Let's talk Geo - overall..custom advice
« Reply #14 on: November 27, 2009, 12:59:52 PM »
Byke, didn't you have a hand in designing the Mike S bars and other products widely used in flat?

I never worked directly in terms of design with dragonfly.
I have worked with other companies that have produced many of my designs, however its only the swiss miss bars that I have put my name on.