Hello Vital MTB Visitor,
We’re conducting a survey and would appreciate your input. Your answers will help Vital and the MTB industry better understand what riders like you want. Survey results will be used to recognize top brands. Make your voice heard!
Five lucky people will be selected at random to win a Vital MTB t-shirt.
Thanks in advance,
The Vital MTB Crew
Isn’t 30.9 the most common?
You might be thinking of 31.6. But then, Specialized, Norco, and I'm sure other brands use 34.9. Seatposts are one of the last areas of MTB standards that's just a total mess with no rhyme or reason for it. What really is the weight difference between a 30.9 and a 31.6 seat post lol we're talking .7 of mm difference.
Nice, been looking forward to riding that bike since I loved the range.
I unintentionally ended up with 4 bikes with 30.9 seat tubes. So now I'm a 30.9 evangelist with only my emotions to support it...
I like the idea of 34.9 because bigger must be better (right?) and all sizes fit with just a shim if necessary.
It's not about weight, it's squeezing out clearance I'm pretty certain. But then again, we are talking about .7mm. Okay it is stupid!
I just had to order my first 30.9mm dropper to fit my new e-bike as that is what it runs. I would have rather had the 31.6 because I already have one and I think a small increase in diameter is helpful for bushing overlap, reducing binding, etc.
435 chainstay across the board...
Brian Cahal has left the chat
Can confirm this is real.
You think the guy at Avalanche suspension is "interesting", Howard Messner was on another level of insane. Ohlins actually cut ties with him for abusing customers pretty much. Sadly he died in 2022 but that man turned shitbox harley davidsons into bikes that were less shit that's for sure. A true suspension genius.
I was his first Australian customer approx 15 years ago, I had to talk to him for weeks to persuade him I wasn't a nigerian scammer lol. I had to go to my local library and use the fax machine to place my order he was that old school. Then have friends I had made from Forums pay him in person. Was the biggest ordeal but once those remote resi ohlins went on my Dyna's it was all worth it.
FWIW nearly every single dropper post offering both 30.9 and 31.6 models use identical internals, including bushings, in both models. I don't think there's an appreciable difference between the two. There's a valid argument with 34.9 but at the same time, now that droppers are mature enough, I'm not sure most people are actually experiencing the issues with 30.9/31.6 posts that 34.9 was meant to solve. Companies are just too good at making em' these days.
A 30.9 post fits everything modern with various shims.
Fun fact about seat tubes: 31.6 just so happens to be the ID of a 1-3/8” diameter, 0.065” tube.
We have 31.6mm seatposts because some engineers were lazy/clever.
Not a fan of the new eeahhh-lins logo 🤨
I ain't putting a shim on my $6,700 base model Evil!
In all seriousness, I've never gotten Cane Creek shims to actually work without some amount of slip.
Don’t forget all the Ducati dorks
I've got a 30.9 post in my 34.9 Sight and it hasn't slipped yet. It does start to creak every couple of months after enough muddy water washes down between the shim and post and takes out all the grease. Slightly annoying, but it's a 3-minute fix when I do my quarterly teardown (cries in PNW winter).
Grease goes between the shim and the post, carbon assembly paste goes between the shim and the frame. Never had an issue with slip or creaks from this area. I own four 30.9 posts and just shim for everything when swapping bikes, if required.
Well, I haven't heard this one before. 🙄
But is it laterally stiff while maintaining vertical compliance?!?
I've got a beer can shim and carbon paste that keeps my post where I want it..
"...are one of the last areas of MTB standards that's just a total mess with no rhyme or reason..." ROFL🤪😁😂😛
Pipe is defined by it's internal diameter whereas tube is defined by it's external diameter. Metal framed seat tubes are built using tube because you can easily get hole saws in the same sizes as tube, whereas reamers are relatively easy to grind or are adjustable. I imagine the 30.9-vs-31.6 issue came about because of available material and from either a frame maker is taking the lead on the design process, or a seat post maker taking the lead.
I recall hearing that BITD Specialized put a lot of time into working out which was the best fit for their product line (using mostly aluminum and steel frames at the time) and 30.9 was their answer.
I spoke to a few seat post manufacturers who ever so slightly prefer 30.9 because the thicker wall better resists being squeezed enough to bind the dropper. They also told me there are many more 31.6mm posts in the world, so they design such that binding isn't an issue.
I-beam dropper from SDG…
I didn't even know SDG still made I-beam saddles.
34,9 mm is not a dropper post related standard. I had a Scott Scale back in my xc racing days in 2005 that had a 34,9 mm seatpost.
As for binding and bushing overlap and the like, there are very few dropper posts that have a 34,9 mm specific upper (Bikeyoke Max series) as opposed to just running a thicker lower/outer tube with the rest of the parts the same as with 30,9 and 31,6 mm posts.
You may wish to edit that 1st sentence to "dropper post related standard". 😉
Thanks. Done.
A thicker outer tube isn't a bad thing in my book. Less prone to suffer from excessive clamping, less prone to binding. This is particularly bad with PNW droppers, where they of en come over-machined and you need to tighten the seat clamp to avoid them from lowering/twisting. Out of tolerance frames (I'm looking at you, Giant!) are another contributing factor.
The new Loam Gen 2 from PNW that we just reviewed uses a 26mm stanchion for the 30.9/31.6, and a 29mm stanchion for the 34.9.
The New offering looks pretty dialed, and I did say in a previous post that I would probably get one if they went back to Boost. The increase in travel, both front and rear, isn’t a huge selling point for me. My local trails are fairly mellow and my daily driver for the last couple seasons has been a 150/135 mullet trail bike. Just small enough to enjoy my local trails and just big enough to handle rougher trails when I travel to real mountains.
So that got me thinking about the new offering run as a mullet with a 150mm fork, run in the high setting. Is there anyway to figure out what that would put the BB at?
https://madscientistmtb.com/bike-geometry-calculator/
Thanks!!! I’ll play around with that
you can ask evil in our forum hot seat, too - https://www.vitalmtb.com/forums/hub/new-evil-offering-forum-hot-seat-ev…