Mountain Bike Reviews Forum banner
1 - 20 of 20 Posts

·
Registered
Joined
·
568 Posts
Discussion Starter · #1 · (Edited)
Greetings from Tampa,

Well here I am in the middle of putting together a 29er. I've got some misc parts and with the help of one of our fellow members, I've got the fork and wheels. I thought I would have a frame by now ... but they are hard to come by ... so I'm pretty much decided on getting a custom build geared hardtail.

Not sure if I'm gonna get many replies to this thread, but figured I'd give it a shot because I could really use some ideas from y'all to influence what I'm doing.

Anyways, if you've had a custom build, I'm wondering how you came up with geometry numbers? Did you copy a production bike, did you create them on your own or did you rely on the builder to spec it for you? Can you share some of your specs (especially TTT and seattube C-C) and your height /inseam?

Did you run across any problems in the design that you wished you done differently?

I look forward to the day when I can contribute ride reports and whatnot instead of just asking questions!
 

Attachments

·
No Reputation!
Joined
·
1,728 Posts
Head Tube

I just told Walt my size and measured some of my other bikes and told him a bit about what I liked about them and he took it from there, I don't know any dimensions on my bike but I liked it so much I bought a second one from him to run with gears. If your builder has made a few, he'll probably more than you about what will work unless you're really into geometry.

One thing you might consider is having the head tube a bit longer at the bottom-below the down tube. Some forks (the reba) can be pretty tight down there with the tall adjustment knobs. You may find yourself with way more knowledge about lower stack height than you bargained for LOL!
 

·
featherweight clydesdale
Joined
·
1,385 Posts
Okay, I used a mix of all three.

With my Airborne hardtail, very little professional help was provided with geometry and tube length. I relied on my experiences with 2 other bikes (I was happy with neither) to select the effective TT length. One of the other bikes was to short, the other two long, I knew my best fit was in the middle. I studied Fisher's geometry and Surly's, but went higher in the BB than Fisher because people used to complain about the height, and I was going to run 180's.

ST length and TT length are a carryover (IMO) from 26 bikes. The head tube is shorter, the HTA is about 0.5 to 1 degree steeper.

I'm about 6' 4.5" with a 35.5 inseam (not pants inseam, use the book to crotch method described on Colarado Cyclist website) Hardtail ended up as follows.

eff TT - 25.0"
ST (center to top) - 21"
STA - 73 deg (fits a wide range and is tried and true)
BB height - 12.75"
HTA 71.5 deg

HT length - I split the difference between the Fisher and Surely. In hindsight, I would have gone a little larger because I only use about an inch of saddle to bar drop.

With the Titus I filled out a form with my measurements, the frame was designed around me and what I liked and didn't like about other bikes I had owned. A drawing was sent for my approval/modification. I wanted a little more ST (20.5 increased to 22" with dropped TT) and a higher BB (12.?? to 12.9). Those changes were made and the frame was built. It looks something like

eff TT 25.0"
ST (center to top) 22.5
STA- 72.8
BB - 12.9 (would now go 13.0/13.1 without blinking)
HTA - 71 deg

Helpful resources

Bike CAD http://www.bikeforest.com/CAD/bikeCAD.html

Seven Cylces website. Check out the geometry and see what numbers change as you go up or down frame sizes.

An old issue of MBA (flame suite on), 2001/2002?? the one with the Ventana Salty review, where RC dedicates several GOOD pages laying out the subtle interplay of frame design and how change affects another.

Good luck.
 

·
Occasionally engaged…
Joined
·
1,772 Posts
Your fork dictates much...

Suicyco said:
...I've got the fork and wheels... Can you share some of your specs (especially TTT and seattube C-C) and your height /inseam?

Did you run across any problems in the design that you wished you done differently?
My height is 6'0", 34" inseam.

My frame numbers:
HTA 72 deg, STA 74 deg, fork rake 50 mm, trail with 50 mm tires is 65 mm, effective TT length 24.25", chain stays 17.45", ~12" bb height, 61 mm of bb drop.

I had determined by experimenting with a 26" wheeled bike that I wanted/needed a quick handling frame (65 mm of trail), and in my book that necessitated a custom fork. You seem to have specified a WB fork, so you pretty much have your front end determined.

I went in knowing what trail measurement I wanted, and knew there were many permutations of fork offset and hta that would get me there. My builder (James at Black Sheep) didn't' have a strong opinion on a given set of HTA and fork offset parameters, so we copied my much loved cyclocross bike measurements. I had done my own measurements on bikes I liked, but I brought them along anyway and he measured them extensively, and my limbs as well.

I let him call everything but the HTA and fork offset, as I had not been able to notice too much effect of head tube length, seat and chain stay length, or STA on comfort and handling over a wide range of dimensions found on previous bikes. The one surprise for me was the STA of 74 degrees, but found it to have resulted in the best-balanced bike I have ever had. He based the STA upon the fact that he found my femur to be "short" for my leg length and would put me in a better position relative to the bottom bracket.

I would not change a thing about the frame -- it is everything I wanted, and then some. You're doing a good thing, educating yourself prior to getting the build. I can't imagine spending the money or time and not being involved in the design -- not making every call, but at least understanding the basis for the different angles and lengths will increase the odds of a successful experience.
 

Attachments

·
Premium Member
Joined
·
48,238 Posts
I picked a builder (Matt Chester). He measured my old bike and me. We talked about what I liked and did not like and how I ride. Discussed the parts/fork I wanted to use.

Matt took it from there. I gave him one dimension, the BB height.

I got the best riding bike I have ever owned.
 

·
Registered
Joined
·
569 Posts
as long as you tell em what they ask...

You'll be in there. Of course, it is good to ChitChat with your respective builder so they get an idea of how you ride, what you ride, what you like and dislike about your previous ride..etc.etc.

Rick Hunter hit my angles perfectly...Sam Hall of Ramblumtick hit mine as well. I ride with Sam so he had a good idea. I spoke with Rick a bunch so he had a good idea. Tell em what you like and/or want...after talking with your builder for a bit, if you get good hits, you are psyched, if not I wouldn't hesitate second opinions....
 

·
assenting member
Joined
·
78 Posts
I talked with my builder. Told him what I was riding, what I liked about it and what I wanted to change. I told the builder the type of riding I like to do. I think he delivered a bike thant answered that. My local riding area offers a different riding style than what I described, and I'm getting lots of pedal strikes. I didn't have a good understanding of the geometry I wanted. I had never ridden a 29"er before and had been on the same bike since '96 (first year Heckler), one size too small by today's standards.

If ordering again, I'd ask for a 55mm BB drop. Maybe less. I have considered getting another frame with a higher BB, but I think this is just a sign that I have "the fever." Good thing I gave up credit cards.

I went from a 130mm stem and 23.25" TT to a 110mm and 24.7". I like the shorter stem, but a dozen rides later and only now is the steering starting to feel normal. It is a big change. I keep expecting the bike to be too big for me, but it just isn't.

The numbers:

Eff TT = 24.7"
ST CC= 18.25"
BB drop = 66mm
HTA = 72
STA = 73.5 and a layback seatpost

Height = 6' 1"
Inseam = 35.75"
Levi's inseam = 34"
 

·
Registered
Joined
·
4,659 Posts
Hey PeT,

Do you think its possible to build a good bike around a WB fork, and still have a custom rigid fork made that will ride well? What I mean is, I'd like to have both a suspension fork and a custom rigid fork made that will both ride similarly without changing geo too much...
:confused:
 

·
Most Delicious
Joined
·
1,413 Posts
I took my 26" bike and steepened the head angle by 1 degree (to 72) by holding the front center distance constant and spinning everything forwards, which lengthened the top tube. I then fine tuned the top tube length to get my handlebars back in the same place with a 15mm shorter stem. I think that made the front center a few mm's longer. BB height (11.8") and seat angle (73) I kept the same. Chainstays I also kept the same, though both bikes were singlespeeds and I tended to run about a 17" chainstay with the gear combo and chain length I use. So I didn't have to change anything there.

My main goal was to come up with something that would feel pretty similar to my old 26" wheel frame (which was also built to my specs, hence the few adjustments to the rest of the geometry). And that it seems to do. On my next 29" frame I'll be a bit more experimental, using a slacker head tube angle and a custom fork with much more rake.
 

·
Occasionally engaged…
Joined
·
1,772 Posts
Certainly...

Sure, you can definitely get a bike that rides pretty much the same -- until you hit something that would compress the suspension. I would recommend a rigid fork that has the same dropout to fork rake distance that the WB has when set up properly for your weight (e.g. - the right amount of sag). But consider having the rigid fork made with a bit more rake/offset. If I remember correctly, the WB has a rake/offset of 38mm -- consider having the rigid fork built with 42 or 45mm of offset for quicker handling. That doesn't satisfy your request for a similar handling pair of forks, but for me the primary reason to use a rigid fork is to get a smaller "trail" measurement (quicker handling) for your bike than can be obtained with a suspension fork.

Wish I Were Riding said:
Hey PeT,

Do you think its possible to build a good bike around a WB fork, and still have a custom rigid fork made that will ride well? What I mean is, I'd like to have both a suspension fork and a custom rigid fork made that will both ride similarly without changing geo too much...
:confused:
 

·
Student of the Bike
Joined
·
810 Posts
Krackity Jones said:
I talked with my builder. Told him what I was riding, what I liked about it and what I wanted to change. I told the builder the type of riding I like to do. I think he delivered a bike thant answered that. My local riding area offers a different riding style than what I described, and I'm getting lots of pedal strikes. I didn't have a good understanding of the geometry I wanted. I had never ridden a 29"er before and had been on the same bike since '96 (first year Heckler), one size too small by today's standards.

If ordering again, I'd ask for a 55mm BB drop. Maybe less. I have considered getting another frame with a higher BB, but I think this is just a sign that I have "the fever." Good thing I gave up credit cards.

I went from a 130mm stem and 23.25" TT to a 110mm and 24.7". I like the shorter stem, but a dozen rides later and only now is the steering starting to feel normal. It is a big change. I keep expecting the bike to be too big for me, but it just isn't.

The numbers:

Eff TT = 24.7"
ST CC= 18.25"
BB drop = 66mm
HTA = 72
STA = 73.5 and a layback seatpost

Height = 6' 1"
Inseam = 35.75"
Levi's inseam = 34"
What length crank arms are you running? Singlespeed? I'm definitely no expert but 66MM drop seems awfully low. What was the BB drop of the older Fishers?
 

·
assenting member
Joined
·
78 Posts
CBaron said:
What length crank arms are you running? Singlespeed? I'm definitely no expert but 66MM drop seems awfully low. What was the BB drop of the older Fishers?
I am running 175mm crank arms on a geared bike.

2004 Fishers were 76mm. Karate Monkeys are 68mm. Comparing to other numbers available when I ordered, it did not seem out of whack. Just not ideal for where I ride most often.
 

·
Recovering Weight Weenie
Joined
·
8,821 Posts
I told Wade @ Vulture:
1. How/where I break bikes
2. What kind of trails I ride
3. How I ride those trails
4. How much I weigh and how big I am
5. what crank length and what fork I'll be using....

and I got a bike that hasn't broken in over 2k miles/1.5 years of use...in my world...that's a lifetime...
 

·
Student of the Bike
Joined
·
810 Posts
Krackity Jones said:
I am running 175mm crank arms on a geared bike.

2004 Fishers were 76mm. Karate Monkeys are 68mm. Comparing to other numbers available when I ordered, it did not seem out of whack. Just not ideal for where I ride most often.
Well...it looks like I validated my comment about "being no expert" :) I was just asking because I'm begining the process of working up frame geo and wanted to know what's worked for some and what has not.

Currently my 26" bike, I'm running 23.5" TT and 120mm stem and don't know my current BB drop. I'm also running 175mm cranks on a geared Steelman. It is my general understanding that the KM has almost established itself as a 29" standard and most don't consider it too low of a BB.

Good thread.
CBaron
 

·
highly visible
Joined
·
3,284 Posts
Also worked with Wade at Vulture ...

Wade measured me, and I told him about the type of riding I do and what I did and did not like about my Karate Monkey, and what I would change.

Wade drew up a diagram, and through the process we talked about pretty much every aspect of fit and geometry: TT length, standover, toe clearance, BB height, exposed seatpost length, my ability to run two specific gear combinations with the chosen chainstay length, etc. With a good custom builder you can just leave all that to them, or (as I did) get into the nitty gritty, as you like.

Since I already had a KM and was pretty happy with its handling, the geometry ended up similar, though certainly not the same. In any event, I ended up with a great bike that works better for me than anything I could have bought off the shelf.
 

·
hispanic mechanic
Joined
·
2,696 Posts
As most have said...

Suicyco said:
Greetings from Tampa,

Well here I am in the middle of putting together a 29er. I've got some misc parts and with the help of one of our fellow members, I've got the fork and wheels. I thought I would have a frame by now ... but they are hard to come by ... so I'm pretty much decided on getting a custom build geared hardtail.

Not sure if I'm gonna get many replies to this thread, but figured I'd give it a shot because I could really use some ideas from y'all to influence what I'm doing.

Anyways, if you've had a custom build, I'm wondering how you came up with geometry numbers? Did you copy a production bike, did you create them on your own or did you rely on the builder to spec it for you? Can you share some of your specs (especially TTT and seattube C-C) and your height /inseam?

Did you run across any problems in the design that you wished you done differently?

I look forward to the day when I can contribute ride reports and whatnot instead of just asking questions!
Selecting a builder is the most important thing. A good frame builder will be able to assess geometry based on your dimensions, riding style, experiences with your current/past bike(s), type of riding you do, terrain that you ride, astrological sign, consultation with the chicken bones, and their past experience. Or something like that.
Brad at Wily did a great job dialing my frameset in for me. I knew there was some things I wanted (high BB for fixed riding, for example) but for the most part I just trusted him. Even though I've ridden for a pretty long time, and worked in the bike biz since the early 90's, I realized that I know exactly jack squat about designing a bike frame. Luckily, there's folks out there that do.
On the other hand, if you do have strong opinions about geometry, find a builder who agrees with you. It'll make for a better experience.
Good luck, and enjoy.

the los
 

·
i like to bicycle
Joined
·
335 Posts
my experience

i decided on soulcraft due to the very small company size and price and the fact they only do custom. i thought a made to order bike would be great. they had me fill in their fit sheet and measure a bike that i thought fit pretty good. i pretty much dictated the TT length, HT length and BB ht. the first time i saw their head angle i about freaked. we discussed about 3 versions before deciding on the exact design. they said to trust them. i'm glad i did. i'm an easy fit tho. 6'1 with 790mm from bb to top of saddle. the things soulcraft think are critical are BB to top of saddle. BB to center of h-bar and h-bar center to nose of saddle. makes a fit triangle. i knew the TT length i wanted from another bike. and i knew i wanted a slightly tall BB ht due to 180mm cranks. so...give the builder the info you think is important and have faith in what they recommend due to your size. feedback from previous purchasers is always key too. that being said i don't think i've heard of a dissappointing experience with any custom fit. true?
 

·
Registered
Joined
·
173 Posts
custom??

Suicyco said:
Greetings from Tampa,

Well here I am in the middle of putting together a 29er. I've got some misc parts and with the help of one of our fellow members, I've got the fork and wheels. I thought I would have a frame by now ... but they are hard to come by ... so I'm pretty much decided on getting a custom build geared hardtail.

Not sure if I'm gonna get many replies to this thread, but figured I'd give it a shot because I could really use some ideas from y'all to influence what I'm doing.

Anyways, if you've had a custom build, I'm wondering how you came up with geometry numbers? Did you copy a production bike, did you create them on your own or did you rely on the builder to spec it for you? Can you share some of your specs (especially TTT and seattube C-C) and your height /inseam?

Did you run across any problems in the design that you wished you done differently?

I look forward to the day when I can contribute ride reports and whatnot instead of just asking questions!
I was looking for a custom but the more I talked, my size was not custom - just your basic large.Find that out. I ended up with a kelly 29er SS ro sham bo (thanks kam) and am in heaven.
Side note - i live 30 min. away from tampa in bradenton. drop me an email for a ride alafia?Balm?TOE?.
 

·
Registered
Joined
·
568 Posts
Discussion Starter · #20 ·
Thanks

Just wanted to follow up on my original thread here and say thanks to all the posters for the wisdom. When I started the thread, I was fully committed to building a custom frame ... and was really taking your advice to heart. However I stumbled across a really good deal on a new '03 GF X-Cal frame. Less than half the price of a custom frame (and that would have been from Spicer so you can imagine pretty low).

Probably won't be as sweet as having a custom built frame, but it will get me started in the 29er world anyways.

So, just wanted to followup so that when I post my new bike, you won't wonder why I was bothering y'all about custom build stuff! Was an interesting thread though for sure.
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top