Long MTB? Why I Cut The Seat Tube On My $3400 Frame.
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Long MTB? Why I Cut The Seat Tube On My $3400 Frame.

September 13, 2019


Hey Guys, Jeff from Worldwide Cyclery here.
We get a lot of questions about bike sizing, and I personally have some strange, unorthodox
views on the whole topic. So I wanted to go over the bike I’m riding now, my personal
history as a rider, and some of the bikes I’ve ridden in the past. This is my current rig. It’s a
2017 Yeti 4.5. It’s a custom build. It’s a size XL, which seems ridiculous because
I’m 5’8″. I’m a short guy and you might imagine I had to make a few modifications
to make this thing work for my height; we’ll get into that a little bit later. So to give you some background, I rode and
raced downhill growing up, I rode motocross, I rode BMX I’ve been on two wheels for
a long time. Riding and racing downhill bikes for so long I got really used to long wheel
base, stable bikes. So it’s pretty simple: The longer the wheel base is, the more stable
the bike will be at speed. That’s a pretty simple theory. Of course there’s still some give and take;
the longer the wheel base is, the bike will feel more like a limousine as opposed to a
sports car. So at high speed in the rough, that long wheel base is ideal. In super-tight
switchbacks or slow technical style riding however, that long wheel base is going to
be kind of a hindrance for you. So there’s definitely give and take. a lot of personal preference involved. Originally when I started riding mountain
bikes I used to like smaller bikes because I primarily came from BMX, and I liked how
agile the bikes were. Then I rode downhill for so long I got really used to long wheel
bases, so now when I have my typical trail bike that I use the majority of the time,
I just want that downhill bike, long wheel base, super stable feel. So as to how that evolved. I obviously rode
Medium frames for quite some time because that’s more my “actual size” as they
would say it. Then I tried a Large frame. I rode an Evil Following Large and I absolutely
loved it. That longer wheel base was amazing and I fell in love with that. Then I hopped
on a Large Yeti 4.5 and I loved that thing. I switch bikes all the time. Being in the
industry it’s easy for me to do, so probably every 6-8 months I’m changing a bike out.
After I ended up selling that Large Yeti, I thought, Okay, what am I going to do
next? Banshee actually had this 29er called the
Prime. It’s kind of an older bike, it’s aluminum, it has this insanely long wheel
base, this massive chain stay, and I figured out that the way Banshees are set up they
have these removable dropouts, so you can actually put the dropout from their 27.5 frame
onto their 29er frame, and I think it makes it another 10-13mms longer. The Large size Banshee Prime 29er was long
to begin with, and then I put this longer chain stay on it. So then I had this monster
bike that was all Batmanned out. I really enjoyed that thing, it was really fun. But
the suspension platform was kind of average, and it was heavy because it was aluminum and I had become too jaded riding carbon bikes for so long. Prior to trying that thing out. So I decided I wanted to ride a Yeti again it was just the best suspension platform. And I wanted to get back on a 4.5, that bike
really suits where I ride most of the time. The majority of the time I’m riding more
mellow stuff, not cross country, not like bike parks or anything, but just like general
trail riding. For most of the riding I do out here, the 4.5 is just phenomenal. But I wanted to take it a step further than
just doing a Large. I already did a Large, so I wanted to do an XL. Problem is with me
being 5’8″, an XL wasn’t going to work because there was just no way I was going
to fit a 125mm dropper post with the size of the seat tube on an XL. So I thought, I’ll
just cut the seat tube. Which everyone thought I was crazy to do that and it was crazy
so I figured, let’s try it out! I took a carbon seat post, and took a Dremel
to it and a drill. I tried different methods to cut it. I don’t wish this kind of pain
on anyone. It was six hours of me sitting in the shop on a Sunday, it took forever,
I had carbon dust all in my hair and on my face. The dust was all over the shop and it
was a total mess. What took me six hours was (it probably took
me about an hour to make the cut on the frame) but the five hours leading up to that I was
testing and practicing. I was taking the carbon seat post and trying to figure out how I could
cut it and drill the correct slots in there without the thing just exploding into a bunch
of carbon flakes. That was a lot harder than I thought it would
be. Putting a drill into it works only if it’s a tiny drill bit. If it’s a larger
drill it starts pulling flakes out, and then how was I going to cut the slot vertically
and have it centered nicely? It was just a lot of work. I ended up using a Dremel for
pretty much the whole thing to make the cut all the way around, and then I used a tiny
drill bit to drill the hole in the front. Then I used a dolphin-nosed style of a Dremel
bit to drill the hole bigger, and then a Dremel to slice it all the way down. So it was mostly
a Dremel. I didn’t want to use a hacksaw because a hacksaw just kept fraying the carbon,
and any big drill bit would fray out the carbon as well. So eventually I did it.I highly DON’T
recommend it. I did it on a brand new frame, which was ridiculous because it was a really
expensive frame. I’m sure it completely voided the warranty. I’m sure Yeti’s not
very happy that I’m telling the public I did it but it’s cool, so we are anyway! I was able to pull it off. I cut it down.
The sizing on these Yeti’s, you can see how the stock tapers down, so this is the
regular 34.9 seat post clamp; it bulges bigger. We had an Evil Wreckoning as a demo bike in
the showroom. I measured that, and it had a 35 mil post in it, and the outer diameter
of the seat tube happened to be the same as this part down here once it bulged out. So
I thought, I’ll just use this seat post clamp. This is actually a seat post clamp
from an Evil, and it’s intended for an Evil Wreckoning that has a 35.0 seat post that
just happens to fit on the Yeti after you chop it off and get past this tapered part. So it’s now the exact size of an actual
Large as far as the seat tube goes, but the top tube is an XL, it’s an XL frame. I have
a 32 mil stem on there, so it’s a super-short, tiny little dink of a stem. It ends up being
a long-top tube but I shortened it up as much as I could with that stem. Super long wheel
base because it’s the XL wheel base, and still a pretty short chain stay. These 4.5s have a pretty short chain stay. I personally love it; it’s super fun. I
mean it’s long, it’s stable, it feels like a downhill bike but it’s super lightweight.
I really enjoy it, but it’s not for everyone. Sizing is one of those things that it’s
very much a personal preference. It’s what you are looking to get out of a bike. Do you
really care about it being agile, or do you care about it being stable? Because it’s
all give and take. It’s just like wheel size, 27.5 vs. 29. It’s
not that one is better than the other. They’re just different. They handle differently in
different situations, and bike sizing is very similar. The bikes handle differently in different
situations. A lot of that is how short that top tube that’s gonna make it easier
to pull up or harder to pull the front wheel off the ground. Also it’s important how
long the wheel base is, because that’s going to make it more stable at speed, or less stable
at speed but more agile in technical situations. So it all depends on what you’re looking
for. A lot of the guys who come in here are more
on the novice side of riding, so I always just recommend what the manufacturers recommend.
If you’re not as far down the path as I am I’ve ridden mountain bikes for over
10 years let’s see, actually over 15 years now and all different types of them.
You know, whether it’s downhill bikes, BMX bikes or cross-country bikes, I’ve ridden
so many different types of bikes that I’ve developed all these crazy preferences. But sometimes it’s not preferences; it’s
just what I feel like. Right now I kind of feel like riding an XL 29er because it’s
fun and it’s what I’m craving right now. Maybe I’ll go on a different route and get
on a Medium size 27.5 bike next because I’ll feel like I wanna ride that! I always tell people, too, don’t overthink
sizing too much. Because as long as your bike isn’t horribly incorrectly sized for you,
and as long as you don’t feel uncomfortable riding the thing, just get a size that works
for you. You want something that fits your preference, fits your riding style. So don’t
think about it, just go ride your bike and have fun! I mean, that’s what mountain bikes
are for! It’s funny to me that in this industry so many people think and debate about all
these different options, when it’s really about just getting a good set-up and having
FUN!

Only registered users can comment.

  1. Dude is really good on camera and doesnt sound like an arrogant goon, should definitely get into tv or broadcasting. My bmx race bike was always a slightly longer frame than I needed; better gates and def more stable at speed. Downside was usually harder yank manuals, oh well.

  2. I love the frame geometry, EXCEPT that STUPID SEAT TUBE! Being able to slam the seat down is a good thing, and Yeti should consider solving this issue

  3. I would suggest that you take a look, what Pole Bicycles(https://www.polebicycles.com/) can offer you. Pole is a small Finnish company and their mtb frames are known for super long top tubes.

  4. Or just lower the seat!! Bad info mate! I've cut seat tubes &post down a few times mostly because I like the look of them slammed and to shave a few G's off. You should leave at least 25cm of seatpost in the frame for strength there should be a mark on the post

  5. That's a major warranty violation!! I suppose that's okay since you're an owner of a shop. I wouldn't dream of doing that…

  6. Well. Cutting a 3500 frame? Terrible advice for a reseller to be giving to customers. Wont be doing anymore business with these guys.

  7. 3 things that should be mentioned. 1, first make sure that the wall thickness of your seat tube is consistent. A lot of times it is thicker in the clamping area and thins out just bellow it. If this is the case, don't cut it! 2, for cutting and drilling, tape BOTH sides with painters tape so you dont get blow out or scratch up the surrounding area, and use a carbon/Kevlar specific tipped drill bit. They have a V cut in the tip. 3, after cutting you need to epoxy all of the freshly exposed carbon fibers, or it will start to delam.
    And so you know where the suggestions come from, I am a composite SME, and former trainer of composite manufacturing for one of the largest US aerospace firms. And will be celebrating my 30th year of mountain biking next year.

  8. I feel the same way about the handling and characteristics of a bigger bike. I’m 5’4 with long legs and ride an 18.5” which is in between a medium and large and people say I’m insane but once that thing is up to speed it feels stable and planted. Everyone has preferences do what feels right not what people want/think you should do.

  9. This is why custom bikes exist lol.
    Also, to cut carbon with a hacksaw use an abrasive blade like this one: https://www.milwaukeetool.ca/accessories/cutting/48-43-0200

  10. Sorry if this question has been asked already but…
    After the cut, was it necessary to drill the hole and the vertical slot?
    What if you just left it alone after you cut/shortened the seat tube?

  11. f you like long bikes try a nicolai geometron. The seattubes are pretty low on all sizes but the wheelbase ist just extremely long.

  12. Hope Yeti is taking note of this, I like the feel of the rear end on a friends SB6 and I've wanted to own a Yeti since the early 90s, but they really need to sort out the crazy long seat tubes (and cracking frames!). I'll take good geo over suspension platform any day.

  13. This is the dumbest shit. (Coming from someone with a mtb national championship jersey, and 10 years in the bike industry.)

    Why in the fuck do I see this as sponsored content? Irresponsible as fuck. @yeticycles This is garbage.

  14. I feel the same way because of 25 years on a dirt bike….Bigger bikes feel more stable going fast and jumping…..Thanks for the great explanation…..Great job on all your videos you explain things very well….

  15. I rather wonder how you got used to long wheelbases riding dh bikes because in my experience, all dh bikes are small. Maybe they are getting bigger now but getting a 26" dh frame that isn't cramped by today's standards is very difficult, for example I have a Lapierre 920DH in size L that's about the same as a current S!

  16. Awesome speaker and presenter skills! An interesting clip on it's own, but having someone with such good camera presence deliver it makes a ton of difference. Keep up the good work 🙂

  17. Great modifications. I like people willing to be the guinea pigs for testing something out. Sounds like something I would do as well.

  18. Been thinking about cutting as much as I can off the seat tube on my Giant Reign…. I can only get about 10-15mm so I'm trying to decide if it would be worth the trouble

  19. I was 5'4" when i got my bike and now i'm 5'9" and the s frame is quite small, i injured my knee a couple of weeks ago and when i was doing a wheelie yesterday i hit the injured knee on my shifter and it hurt like hell😂😂

  20. Great video mate. Have you checked out Sick Bicycles? They design and construct frames crazy long and slack with even crazier geometry. I think their products might interest you.

  21. Nice vid man..im a big guy but all my bikes are M because i feel like im riding i dirt bike on something bigger and also i rather have 26s unless its my trail bike

  22. I´m 166 cms (something like 5feet 5inches) and cannot be more agree with you. I´m 40 y/o, and i had bikes from 13.5" XXS to 18.5" (Large). I think the best is to have two bikes, and is what i do, one a 15" small short nimble frame and other 16.5" (Small frame) bike with long wheelbase. Before, I liked more the little small, a year o so i prefer the long bike. I think that if there is not toe overlap and no standover problems you can ride whatever bike you want.

  23. fyi for anybody thinking about doing this….you could just install a Oneup 150mm dropper and adjust the travel down to 100 mm.

  24. Great video I went through that problem buying my specialized Stumpjumper I'm 5 9 and 1/2 so I can either ride a large or a medium and without being able to demo one off road I went back and forth in my mind for days I finally settled on the medium because I had more clearances between me and the bike and it felt more natural but both of them were great

  25. I've seriously considered doing this to a custom NukeProof Scout XL frame I just built. I'd been used to a Ragley size L….so on the Scout's maiden voyage, well I caught me boys on the rear of the saddle a half dozen times I just the first hour of use! I mean… DAMN!

  26. I'm considering buy a sb5.5 and putting a -2 degree works components headset into it and an offset bushing to bring in back a half degree, and keep the bb height at roughly stock… am I crazy? would shorten the effective top tube and yes, I'd size up to a large..

  27. My two cents on getting freaked out about bike sizing is that as the price of bikes continues to go up people are more and more worried they’re going to make a very expensive and wrong decision. I am currently trying to decide between a large or extra large frame and this video has helped me quite a bit. I know that wasn’t what you were trying to do but thanks for the tips anyway. I find myself completely between the two frame sizes and I am very concerned that buying to big is going to be a problem in the future.

  28. May i ask your honest opinion of a 2018 Santa Cruz Hightower LT? What did you like/dislike? It's now an obsolete design so I doubt anyone will be offended by any honest negatives.
    Thank you

  29. YOUR NOT STRANGE BRO..THAT LONG AZZ SEAT TUBE IS A PAIN IN THE ASS.IMA SELL MY $800 TREK(which I didn't pay $800)BECAUSE OF IT…NICE VID.

  30. Hi can anybody help me, I just grabbed a bike off fb marketplace (was only £30 how could I say no) nice giant mtb. Bit too big for me, I'm around 5"6/7 and the frame says it's an XL. I wanna cut the seat frame bit down so I can actually touch the floor from the saddle. I only need a couple inches. Just wondering if it would mess up the bike or if it's fine to do. Thanks!

  31. want to chop my Intense spider seat post for the same reasons you did the Yeti, I'm just not sure I have the cahjones to touch the frame with a dremmel that is actually spinning at 1600, rpm …..

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