Official Mountain Biking thread (MTB)

[Chris Pringle]

Originally Posted by Tambohamilton;29483843[I

[/I]]Well, I'd like to chime in here and yell at some folk

I've been a MTB designer for 15 years or so now, just for context - not dick measuring.

My only bike is a 27.5" hardtail, not because it's more efficient, but because I like it. It's not faster than a comparable FS either up or down hill, except maybe on smooth trails without big features (jumps, drops, etc).

If I were to advise someone joining the sport, I'd say get a 29er hardtail with good geometry. Geometry is king. Upgrade tyres if desired, but don't just target light weight. After that I'd probably upgrade the forks. Get a reliable dropper post.

Hardtails are cheaper, like for like, and will teach good riding habits.

However, if anyone wants to go fast up or down hill, the answer is FS and money. Like I say, a hardtail is only faster on smooth trails, assuming both are well designed.

My next bike will likely be a 120 or 140mm 29er FS, in at least a year. I love my hardtail, but my ankles hurt and it's annoying to have to drag around a DH rear tyre with a cushcore insert, and occasionally still pinch flat.

Oh, and avoid plus size tyres, unless you want a laugh.

Appreciate your perspective, but you lost me on your last sentence. Since you have firsthand knowledge of bike design, could you please elaborate?

[Conissah]

Originally Posted by Chris Pringle

Appreciate your perspective, but you lost me on your last sentence. Since you have firsthand knowledge of bike design, could you please elaborate?

2.8” wide tires (or higher) are considered plus sized. My 2 Treks have come in 29x2.6”, meaning they aren’t plus sized. My neighbor rides a Specialized Fuze Comp that came with 27.5x3.0” tires, meaning plus sized.

[Conissah]

Been pushing myself on the full squish, getting very comfortable on the bike. Did a smooth 16 miles today at my favorite local park and set a bunch of new PRs (including a new top speed PR). Had the Fuel EX5 for a little over 2 weeks, already almost 60 miles in, absolutely loving it.

[Run Silent]

Originally Posted by Conissah

Been pushing myself on the full squish, getting very comfortable on the bike. Did a smooth 16 miles today at my favorite local park and set a bunch of new PRs (including a new top speed PR). Had the Fuel EX5 for a little over 2 weeks, already almost 60 miles in, absolutely loving it.

Jeez man, that is a screaming speed for so much elevation.

[Chris Pringle]

Originally Posted by Conissah

2.8” wide tires (or higher) are considered plus sized. My 2 Treks have come in 29x2.6”, meaning they aren’t plus sized. My neighbor rides a Specialized Fuze Comp that came with 27.5x3.0” tires, meaning plus sized.

Thanks, that part is clear. The question to Tambohamilton pertains to why he thinks plus tires should be avoided on a hardtail.

By the way, you seem to be having a great time on the new bike. Keep it up!

[freakystyly]

Got a butt boo boo last time I went out, should know better than to try jumps on the hard tail by now. Pedals slipped and the saddle rails got bent when I came down, the replacement is ready to go on.

[Run Silent]

Originally Posted by freakystyly

Got a butt boo boo last time I went out, should know better than to try jumps on the hard tail by now. Pedals slipped and the saddle rails got bent when I came down, the replacement is ready to go on.

Ouch!

[Tambohamilton]

Originally Posted by Chris Pringle

Appreciate your perspective, but you lost me on your last sentence. Since you have firsthand knowledge of bike design, could you please elaborate?

So tyres rely on hysteresis in the rubber of the tyre in order to provide some sort of damping. Lighter tyres (less rubber and generally former compounds for efficiency) have less damping and feel more sketchy than heavy tyres. Think of the muted ride quality of DH tyres, Vs xc tyres pinging and skipping along the trail. For normal size tyres (2.3-2.4" ish) we can generally strike a decent balance between weight and drag and grip and damping. But the larger the tyre, the more that has to be skewed towards light weight in order to just keep the system weight reasonable.

So plus size tyres do get a lot of grip at low speeds, but get more and more unruly as you go faster. Which is the opposite of good!

There are also quirks and problems with handling which are in a similar vein, for plus tyres.

All that said, fat bikes are hilarious fun! But they're essentially fun for all the wrong reasons. And if you already have a plus bike, crack on! No harm in it. I just wouldn't recommend them to anyone

[Run Silent]

Hooray. New bike day for me. Christened with a full day at the bike park.

[Chris Pringle]

Originally Posted by Run Silent

Hooray. New bike day for me. Christened with a full day at the bike park.

Congrats! How did it perform?

[Chris Pringle]

Originally Posted by Tambohamilton

So tyres rely on hysteresis in the rubber of the tyre in order to provide some sort of damping. Lighter tyres (less rubber and generally former compounds for efficiency) have less damping and feel more sketchy than heavy tyres. Think of the muted ride quality of DH tyres, Vs xc tyres pinging and skipping along the trail. For normal size tyres (2.3-2.4" ish) we can generally strike a decent balance between weight and drag and grip and damping. But the larger the tyre, the more that has to be skewed towards light weight in order to just keep the system weight reasonable.

So plus size tyres do get a lot of grip at low speeds, but get more and more unruly as you go faster. Which is the opposite of good!

There are also quirks and problems with handling which are in a similar vein, for plus tyres.

All that said, fat bikes are hilarious fun! But they're essentially fun for all the wrong reasons. And if you already have a plus bike, crack on! No harm in it. I just wouldn't recommend them to anyone

Thank you for the thorough explanation. My personal experience with plus tires has been overall positive on hardtails - a little sluggish but that’s all. My only concern is that plus tires are particularly popular with 27.5 wheels which seem to be declining quickly in popularity against 29er’s. I’ve read a lot of the issues with plus tires were mainly with full suspension bikes which forced bike manufacturers to dial things back to 2.6” tires a few years ago.

[Tambohamilton]

Yeah, the issues with FS and plus tyres are really the same ones of a lack of damping in the tyre; you get very odd crosstalk between the response of the tyre and the response of the suspension.

Watch some of Pinkbike's Huck to flat videos. There aren't any of plus bikes that I can remember seeing, but they give an impression of how the tyre and suspension are interacting. A lot of the time the tyre rebounds completely off the ground after the initial contact, even though the frame/rider is still going down

[Run Silent]

Originally Posted by Chris Pringle

Congrats! How did it perform?

Loved it! Nice to be back to a more appropriate bike for my riding style. Bike really enjoyed being in the air and provided quite a bit of confidence.

[Conissah]

Originally Posted by Run Silent

Loved it! Nice to be back to a more appropriate bike for my riding style. Bike really enjoyed being in the air and provided quite a bit of confidence.

New bike looks sweet! What do you mean by "more appropriate for your riding style?" You had a Fuel EX previously right? Just wanting to hear your impressions on the bike compared to the previous one.

[Run Silent]

Originally Posted by Conissah

New bike looks sweet! What do you mean by "more appropriate for your riding style?" You had a Fuel EX previously right? Just wanting to hear your impressions on the bike compared to the previous one.

So nothing wrong with the Trek - but I do about 50% bike park riding, 25% downhill, and maybe another 25% mix of normal trail riding and XC. The Trek geometry wasn't very good for the bike parks - didn't want to jump well and on the steeps, I felt as though I would go over the bars. At the downhill parks, it was completely out of it's element - far too short a wheel base and not enough slack in the head angle. This new bike is much more 'playful'.

In addition - I have super short legs and the trek's tend to have high stand over heights and limited dropper clearance (100mm on small) due to the kink in the seat tube. As such, I needed to be on a Small to fit on a Trek and that caused the reach and wheel base to be too small for me - made me feel like a bear on a unicycle at a circus. I moved up to a medium on the new bike - fits much better - and with the straight seat tube, I am running a 180mm dropper with a much better fit. See key diffs below:

Wheelbase: Trek 1140mm vs Transition 1220mm
Reach: Trek 415mm vs Transition 460mm
Standover: Trek 707mm vs Transition 673mm
Head angle: Trek 66.5* vs Transition 63.5*

Trek was a great trail bike - but not well suited to the type of riding I do mostly.

[Run Silent]

Nice ride yesterday with the warm temps. Only downside was the first half of the ride, nothing was blown off, so twice I slid down the side of a hill as I couldn't see the trail due to all the leaves.

Then the second half was awesome, but oh so dusty! By the time I was finished, me, the bike, the ground, and the tires were all the same color.

[Run Silent]

May have been below freezing with a light snow falling, but still got out there for 3hrs. I question my sanity.

Not bad for an old, fat dude.

[Run Silent]

Went snowboarding on Saturday, bike park on Sunday. Lol, only in TN.

[Ennoch]

Originally Posted by Tambohamilton

So plus size tyres do get a lot of grip at low speeds, but get more and more unruly as you go faster. Which is the opposite of good!

There are also quirks and problems with handling which are in a similar vein, for plus tyres.

All that said, fat bikes are hilarious fun! But they're essentially fun for all the wrong reasons. And if you already have a plus bike, crack on! No harm in it. I just wouldn't recommend them to anyone

Just discovered this thread (usually use the one in the UK OT section). As you say, plus tyres are great for bumblers, my dad's Trek Fuel with them is superb for him on rough Scottish hill tracks as he's in his sixties and not thrashing it - they give him grip at the point he wants it, and he isn't sliding the bike around so progressive breakaways etc are something he doesn't need. In contrast I really dislike large tyres (anything over a modern 2.4" basically); they dull steering response and accuracy, they bounce, and are basically a large and uncontrolled spring, much like the old balloon tyres were in F1. And if you ride hard you can either get them soft enough that they have traction but you then smash the rim on rocks and get squirm, or hard enough to dispel the latter two but then have zero traction. I'm not even a fan of the square profiles that modern wide rims create; I'd far rather a rounder profile which gives marginally less peak grip but a far smoother transition from grip into slide, which is what gives you control when pushing, especially when it's slick.

Fat bikes are great if you're trying to ride across snow (like in Canada/VT etc) or the Sahara, but for riding around a trail centre they're just comically bad and only really chosen by slightly weird types.

[Lady Jane]

Anyone cycling during the winter?

[freakystyly]

My regular place looks weird without leaves, can't do it.

[Tambohamilton]

Originally Posted by Lady Jane

Anyone cycling during the winter?

Attachment 3041379

Winter rides are the best rides. Had a great time out on the bike yesterday