Old school geometry- Mtbr.com
Results 1 to 12 of 12
  1. #1
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    21

    Old school geometry

    I think there's still a place for old-school MTB (ATB?) geometry in our diversified little mountain bike world; a mellow, cruising kind of ride for those who don't want or need to go fast, but just want to plonk around in the woods.

    My first real ride was a lower-end Raleigh: a shallow angled, short top tube, long chainstayed and front-center, short stem, riser bar wonder that I used to ride everywhere, complete with jeans, sneakers and Metallica shirt. Okay, it was a pig in tight technical singletrack at speed and the front end wandered like mad when climbing, but it descended like a fiend and I had just as much laughs plonking through the woods on that thing as I did with later, sleeker bikes and lycra.

    The past through rose-coloured glasses? misplaced nostalgia? a mid-life crisis at 31? Who knows, but I'm glad this forum's here, because alot of these bikes come from 88-93, the years I really began riding and reading bike mags, so it brings back fond memories. Anyway, keep the pictures and the stories coming, looking forward to them all...

    Pax

  2. #2
    artistic...
    Reputation: colker1's Avatar
    Join Date
    Jan 2004
    Posts
    7,553

    short wheelbases are gone?

    Quote Originally Posted by surlyVEE
    I think there's still a place for old-school MTB (ATB?) geometry in our diversified little mountain bike world; a mellow, cruising kind of ride for those who don't want or need to go fast, but just want to plonk around in the woods.

    My first real ride was a lower-end Raleigh: a shallow angled, short top tube, long chainstayed and front-center, short stem, riser bar wonder that I used to ride everywhere, complete with jeans, sneakers and Metallica shirt. Okay, it was a pig in tight technical singletrack at speed and the front end wandered like mad when climbing, but it descended like a fiend and I had just as much laughs plonking through the woods on that thing as I did with later, sleeker bikes and lycra.

    The past through rose-coloured glasses? misplaced nostalgia? a mid-life crisis at 31? Who knows, but I'm glad this forum's here, because alot of these bikes come from 88-93, the years I really began riding and reading bike mags, so it brings back fond memories. Anyway, keep the pictures and the stories coming, looking forward to them all...

    Pax
    looong top tubes are the norm now. finding a 41 in wheelbase bike, except IF, is a difficult... that's what i ride and the next bike will be custom to maintian my old schjool short top tubes.

  3. #3

    Reputation:
    Join Date
    Jan 2004
    Posts
    995
    Yep, personally, I've yet to ride anything new bikes that handle as fast and dangerous as the race bikes of the early-mid 90's. Tight wheelbases, steeper angles, lower front ends, and longer stems make for more control, and wildly fun trail riding. Nothing handles like a garbage scow in the high seas like a modern freeride bike on your average xc trail. Leave it to marketing to figure out that what's selling freeride bikes will sell sc bikes...

  4. #4
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,052
    Quote Originally Posted by flyingsuperpetis
    Yep, personally, I've yet to ride anything new bikes that handle as fast and dangerous as the race bikes of the early-mid 90's. Tight wheelbases, steeper angles, lower front ends, and longer stems make for more control, and wildly fun trail riding. Nothing handles like a garbage scow in the high seas like a modern freeride bike on your average xc trail. Leave it to marketing to figure out that what's selling freeride bikes will sell sc bikes...
    this all leads me to a geometry question: when rolling down steep, slow technical stuff, is the short bike or the long one going to be less likely in you jumping over the bars?
    -on the short top tube bike, you have the advantage of being able to lean way back off the back of the bike, unweighting the front axle. BUT... let's take the situation where you have to roll off, say a 2' tall 90deg wall onto flat. on the short bike, when the front wheel hits the ground, the angle the bike takes to the ground is very steep compared to that of the long bike.
    -however, the long bike is going to have the disadvantage of not allowing the rider stretch himself far enough out over the rear axle to unweight the front end.
    thoughts?
    as for liking the old geometries better, i think the slack, short front end, long rear, low bb bikes of the 80's were like that to make unsuspended bikes go downhill better. but i also think the early 90's steep, low front end, long stem setups were a disaster for riding down steep stuff, which is one of my favorite things to do. i think in this case the newer bikes are a good compromise between the two. just by changing stem length from 120mm to 75 you can turn your twitchy xc bike into something a little more suited for riding back down.

  5. #5
    mtbr member
    Reputation: Fillet-brazed's Avatar
    Join Date
    Jan 2004
    Posts
    7,696

    I agree

    For anything steep or rough the weight distribution needs to be more rearward biased. That is what the freeride bikes are. Whether or not these bikes get used that way with all who purchase them is another question. Yes, a bike with heavy rear weight distribution will handle terribly on flatter, quicker terrain and especially (obviously) uphill.

    The late 80s to mid 90s bikes with the 150 long and low stem and long tt dont feel so great to me any more. But back then that was the norm and lots of people carried good speed on them. Maybe Im just no longer used to it but they feel real sketchy now. They are great for climbing and then thats about the extent of it. Tomac and Ned both kinda started using higher, shorter stems than what was the trend and now this seems to be the more widely used position currently for XC.

    Its all about weight distribution. Ideally we could change it as we crest each hill. Some of those old XC rigs were hard to get any weight off the front wheel!

  6. #6

    Reputation:
    Join Date
    Jan 2004
    Posts
    995
    Yep, you pretty much hit it on the head. Longer, whether front or rear is simply going to be more stable than shorter. With Shimanos drivetrain limitations restricting the variance of the rear though, what's more noticable frame to frame is the top tube/stem proportion, and where that puts the front wheel under your center of mass when nosing up or down. As is plain to see, when descending, a shorter tt is going to tuck the wheel up under you, which brings you that much closer to going over the entire time. Means you really have to be active on the bike. Means you're going to be moving your weight around a lot more, and attempting to handle the bike from odd positions, creating greater and more opportunities for disaster. On the other hand, if you get good at this sort of riding, you get a better workout, and can utilize your shorter wheelbase and increased leverage on the bars (longer stem) to handle the pants off just about anyone. Still, it's a painful process, and a lot of work. Not sure altogether worthwhile one for well, really anybody. Like everything, depends on the usage.

    I do know there are a lot of poor unfortunate shmoes that have been suckered into buying heavy roiling hogs as the latest and greatest in cross country race bikes here in the midwest. Laughable at first, till you realize how much people are scrificing to spend every last penny on the weighty authoritative advice of bike shop sales kids, on a two wheeled Monstertruck, to ride on cross country ski trails in Wisconsin & Minnesota, where the maximum elevation difference across the entire state is a whopping 400 feet or so... As someone here is quick to point out, there are people racing in this sport that have never even ridden a rigid bike. I sometimes let those people ride one of mine, so they can see firsthand, by contrast, how inefficient their slugs are. The reactions are generally pretty entertaining.


    Ned Overend : eNd Over end
    Surely you're joking, Mr...!

  7. #7
    artistic...
    Reputation: colker1's Avatar
    Join Date
    Jan 2004
    Posts
    7,553

    i don't like long bikes...

    Quote Originally Posted by flyingsuperpetis
    Yep, you pretty much hit it on the head. Longer, whether front or rear is simply going to be more stable than shorter. With Shimanos drivetrain limitations restricting the variance of the rear though, what's more noticable frame to frame is the top tube/stem proportion, and where that puts the front wheel under your center of mass when nosing up or down. As is plain to see, when descending, a shorter tt is going to tuck the wheel up under you, which brings you that much closer to going over the entire time. Means you really have to be active on the bike. Means you're going to be moving your weight around a lot more, and attempting to handle the bike from odd positions, creating greater and more opportunities for disaster. On the other hand, if you get good at this sort of riding, you get a better workout, and can utilize your shorter wheelbase and increased leverage on the bars (longer stem) to handle the pants off just about anyone. Still, it's a painful process, and a lot of work. Not sure altogether worthwhile one for well, really anybody. Like everything, depends on the usage.

    I do know there are a lot of poor unfortunate shmoes that have been suckered into buying heavy roiling hogs as the latest and greatest in cross country race bikes here in the midwest. Laughable at first, till you realize how much people are scrificing to spend every last penny on the weighty authoritative advice of bike shop sales kids, on a two wheeled Monstertruck, to ride on cross country ski trails in Wisconsin & Minnesota, where the maximum elevation difference across the entire state is a whopping 400 feet or so... As someone here is quick to point out, there are people racing in this sport that have never even ridden a rigid bike. I sometimes let those people ride one of mine, so they can see firsthand, by contrast, how inefficient their slugs are. The reactions are generally pretty entertaining.


    Ned Overend : eNd Over end
    Surely you're joking, Mr...!
    my ibis has a 41in wb.. my mikkelsen has a 41.5 (perfect) w/ 17.25 cs. the mik is the best handling bike in the tight vertical slippery dangerous trails around here. i had a litespeed obed with 42in wheelbase and well, it was no fun. too safe but no fun like i was inside a tour bus in the trail and wanted to climb down and get a taste of the world, bought the ibis mojo. still not as magical as the mikkelsen ( the botom bracket is 12.5in high w/ a rigid non corrected fork..).
    whenever i play shopping for a new bike, i see the geom. and give up= hardtails w/ 42in? no thanks.

  8. #8
    mtbr member
    Reputation: Fillet-brazed's Avatar
    Join Date
    Jan 2004
    Posts
    7,696

    It depends

    Quote Originally Posted by colker1
    my ibis has a 41in wb.. my mikkelsen has a 41.5 (perfect) w/ 17.25 cs. the mik is the best handling bike in the tight vertical slippery dangerous trails around here. i had a litespeed obed with 42in wheelbase and well, it was no fun. too safe but no fun like i was inside a tour bus in the trail and wanted to climb down and get a taste of the world, bought the ibis mojo. still not as magical as the mikkelsen ( the botom bracket is 12.5in high w/ a rigid non corrected fork..).
    whenever i play shopping for a new bike, i see the geom. and give up= hardtails w/ 42in? no thanks.
    For tighter, slower speed (<25mph) stuff, I think shorter is better. And those are the types of trails, for the most part, that we like to ride. But theres a few spots in an area I ride in where youre nearing 45-48mph down a pretty gnarly, rutted trail. The short bikes here are SCARY.

    So, I guess, it just depends how fast your trails are. If youre doing fire road bombing, something with a 41" wheelbase is not gonna cut it.

  9. #9
    artistic...
    Reputation: colker1's Avatar
    Join Date
    Jan 2004
    Posts
    7,553

    depends!!

    Quote Originally Posted by Fillet-brazed
    For tighter, slower speed (<25mph) stuff, I think shorter is better. And those are the types of trails, for the most part, that we like to ride. But theres a few spots in an area I ride in where youre nearing 45-48mph down a pretty gnarly, rutted trail. The short bikes here are SCARY.

    So, I guess, it just depends how fast your trails are. If youre doing fire road bombing, something with a 41" wheelbase is not gonna cut it.
    a short wheelbase with a LOW bottom bracket works (hmmm. like a road bike?).. or a short whelbase coupled with a tall bb and looong cs will work as well (like the mikkelsen).
    the obed, with 42 in wb, 16.9 cs and 12in bb... felt like riding my refrigerator; anywhere.

  10. #10
    mtbr member
    Reputation: Fillet-brazed's Avatar
    Join Date
    Jan 2004
    Posts
    7,696
    Quote Originally Posted by colker1
    a short wheelbase with a LOW bottom bracket works (hmmm. like a road bike?).. or a short whelbase coupled with a tall bb and looong cs will work as well (like the mikkelsen).
    the obed, with 42 in wb, 16.9 cs and 12in bb... felt like riding my refrigerator; anywhere.
    I cant say Ive had the chance to compare two bikes with the same WB but with different bb heights. A lower bb would definitely help keep the weight low behind the front wheel, avoiding the "over the bars" feeling which is not good at speed.

    A road bike really doesnt have the need to transfer much weight to the rear wheel. For one, paved roads only get so steep, and two, roads are relatively (nothing thats gonna send you otb) smooth. If anything, usually in corners youre in the drops trying to put more weight up front.

    Unfortunately low bbs dont work well in my area. I have to have one slightly higher than most due to many of our trails being off-camber and on side hills. Gotta be able to pedal. But, lower is better from a handling standpoint I think.

  11. #11

    Reputation:
    Join Date
    Jan 2004
    Posts
    4
    Hmm, I could spend a grand on an IF frame or keep riding my 2001 Raleigh M20 which I originally paid $135 for on closeout. Wheelbase: 41.5 inches baby. Gotta love that.

  12. #12
    MTBR Tool
    Reputation: Srexy's Avatar
    Join Date
    Jan 2004
    Posts
    831
    Great discussion everyone. Here's my 2c. I recently went from a '91 custom built steel h/t that was designed for the twisty English mud and cack trails to a Giant XTC DS1 f/s that was obviously designed w/stability in mind. If I recall correctly the head angle on the h/t is either 71 or 71.5 and the chainstays are longish at 16.5" or 17" (don't recall the seat tube angle either...). It has a long reach but I don't recall the top tube length - the stem is 120mm however. I don't have the overall w/b measurements. The characteristics of this setup are that it's very agile in singletrack and honestly - pretty decent on the descents (the limiting factors here in AZ - pinch flats and the v-brakes). This is not a wheelie bike!!

    Segue to my new f/s and although I'm loving the disc brakes and the confident descending, I'm not enjoying the constant bashing that my pedals receive (low bb height) nor the lazy front end which is constantly washing out on me unless I get out of the saddle to get around the tighter corners. I am considering increasing the stem length from 110mm to 120mm or 135mm and swapping out the laid-back seat post for a "straight-up" design but am wondering what effects that will have on the climbing/descending characteristics of this bike (both of which are pretty good)



Similar Threads

  1. Body geometry and fork travels
    By Disaster in forum Shocks and Suspension
    Replies: 2
    Last Post: 01-24-2004, 11:09 PM
  2. How to "tighten up" front geometry on NRS?
    By Srexy in forum General Discussion
    Replies: 7
    Last Post: 01-21-2004, 04:30 AM
  3. Replies: 1
    Last Post: 01-12-2004, 07:32 AM
  4. Fuel 90 & Trek 8000 -- geometry
    By Cero in forum Trek
    Replies: 6
    Last Post: 01-11-2004, 08:49 AM
  5. Ventana colors webpage
    By Ventanarama in forum Ventana
    Replies: 7
    Last Post: 01-09-2004, 07:26 AM

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.