BMC AC01 off road

pjtn
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BMC AC01 off road

Postby pjtn » Mon Apr 24, 2017 1:59 am

I have a BMC AC01 Alfine 11 bike and have been getting a little curious about taking it onto some fire tracks. The bike has 28c tyres and DT Swiss R522D rims and I understand the frame to be quite stiff.

Would it be ok to take this bike off of the sealed tracks? I'm not sure if it's very well suited to this kind of riding or if it could get wrecked. We would not be riding fast or attempting jumps.

I have seen some of the road bikes being marketed for off-road riding like the Focus Paralane and they have the same rims and tyre size.

Usernoname
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Re: BMC AC01 off road

Postby Usernoname » Mon Apr 24, 2017 7:03 am

I've ridden my merida ride 5000 roadie on fireroad and single track with 25c tires. Just avoid ruts and rocks, they will ding any rim hit hard enough. The smaller tire size = higher pressure = rough ride and more prone to pinch flats and rim dings.

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Duck!
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Re: BMC AC01 off road

Postby Duck! » Mon Apr 24, 2017 9:06 am

Bikes are a lot more robust than people give them credit for. A bit of gravel & tree roots & stuff will be fine, you might just pinged around a bit on looser stuff.
I had a thought, but it got run over as it crossed my mind.

pjtn
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Re: BMC AC01 off road

Postby pjtn » Mon Apr 24, 2017 1:29 pm

Is it a good idea to lower the tyre pressure before taking it off-road?

I'm 70kg and currently run the tyres at 70psi.

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Duck!
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Re: BMC AC01 off road

Postby Duck! » Mon Apr 24, 2017 2:02 pm

A bit, but not too low, because you're more likely to get pinch flats and damage the rims.
I had a thought, but it got run over as it crossed my mind.

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Re: BMC AC01 off road

Postby Calvin27 » Mon Apr 24, 2017 8:18 pm

I had an alfine flat bar similar to yours. Did lilydale wrburton on it with 32c tyres at 75psi for 78kg rider (porked up a bit now lol).
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Re: BMC AC01 off road

Postby chriso_29er » Mon Apr 24, 2017 10:36 pm

I do a lot of rail trail / dirt road work on 28c tyres. No problem.
I have had one flat, but that was after launching air off a washout and landing on a rock on a MTB track in the dandenongs lol.
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pjtn
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Re: BMC AC01 off road

Postby pjtn » Tue Apr 25, 2017 11:11 pm

Thanks for all of the replies.

I will have to check what the tracks are looking like, they can get quite rough. But everyone's advice has made me more keen to give it a go.

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Re: BMC AC01 off road

Postby CycloTron » Thu Apr 27, 2017 12:53 pm

My commute includes a fair bit of gravel/fire trails and my commuter is a flatbar with an Alfine hub and I used to have 28c Marathon Plus tires, which proved adequate but slightly dicey on looser sections of dirt/gravel, so you should be fine. Ride was harsh though, even with a front Headshok fork.

I've now changed to a rigid fork but offset that with tubeless Schwalbe G-One tires at ~45psi - heaven!

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Re: BMC AC01 off road

Postby pjtn » Thu Apr 27, 2017 12:58 pm

CycloTron wrote:My commute includes a fair bit of gravel/fire trails and my commuter is a flatbar with an Alfine hub and I used to have 28c Marathon Plus tires, which proved adequate but slightly dicey on looser sections of dirt/gravel, so you should be fine. Ride was harsh though, even with a front Headshok fork.

I've now changed to a rigid fork but offset that with tubeless Schwalbe G-One tires at ~45psi - heaven!


I have been thinking of changing to 32c tyres if we decide to ride off-road more often. The current tyres are quite new so it's probably best to try them out first.

I don't want to lose performance when on the sealed tracks too much, though.

CycloTron
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Re: BMC AC01 off road

Postby CycloTron » Thu Apr 27, 2017 2:15 pm

pjtn wrote:
CycloTron wrote:My commute includes a fair bit of gravel/fire trails and my commuter is a flatbar with an Alfine hub and I used to have 28c Marathon Plus tires, which proved adequate but slightly dicey on looser sections of dirt/gravel, so you should be fine. Ride was harsh though, even with a front Headshok fork.

I've now changed to a rigid fork but offset that with tubeless Schwalbe G-One tires at ~45psi - heaven!


I have been thinking of changing to 32c tyres if we decide to ride off-road more often. The current tyres are quite new so it's probably best to try them out first.

I don't want to lose performance when on the sealed tracks too much, though.


Indeed you'll find that your current setup will do just fine. If and when you do switch over to wider tyres, I would recommend seriously considering going tubeless. The G-Ones I now use are 35mm but handle road riding just fine, I can't say they're any slower or roll any worse.

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Re: BMC AC01 off road

Postby pjtn » Thu Apr 27, 2017 3:29 pm

What is the maintenance like with the tubeless tyres? I've heard you are supposed to apply something every month or so.

Tubeless is very appealing because you can repair punctures without taking it off. Which would make it much easier with the rear hub.

And 32c tyres should be less likely to get a puncture in the first place.

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Re: BMC AC01 off road

Postby CycloTron » Fri Apr 28, 2017 3:59 pm

pjtn wrote:What is the maintenance like with the tubeless tyres? I've heard you are supposed to apply something every month or so.

Tubeless is very appealing because you can repair punctures without taking it off. Which would make it much easier with the rear hub.

And 32c tyres should be less likely to get a puncture in the first place.


So, tubeless setups require sealant inside the tire which stops air from leaking and plugs small punctures on the go. The sealant eventually evaporates and will need to be replenished. You may need to do this around every 6-12 weeks or so, according to the manufacturers of the sealant.

Tubeless tires with sealant will seal off small (usually <5mm) punctures with sealant without you having to do anything. However, if there is a large enough hole that the sealant is defeated, you'll still have to remove the tire and install a tube to get you home, generally. I haven't had this happen to me, but then again, I don't ride through rock gardens etc. on my commute!

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Re: BMC AC01 off road

Postby bychosis » Fri Apr 28, 2017 4:14 pm

Agree with Duck. Bikes are pretty strong overall, even road bikes are designed to cope with cobbled streets in Europe and potholes everywhere. Check out 'road bike party' on youtube.

I rode my old steel roadie on fire road equivalent stuff plenty of times on 23mm tyres. Just had to be more careful than when riding something with fat tyres.
bychosis (bahy-koh-sis): A mental disorder of delusions indicating impaired contact with a reality of no bicycles.

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Re: BMC AC01 off road

Postby Duck! » Fri Apr 28, 2017 6:49 pm

pjtn wrote:What is the maintenance like with the tubeless tyres? I've heard you are supposed to apply something every month or so.
Tubeless tyres require a liquid latex sealant, which usually needs to be topped up once or twice a year. The required quantity of sealant varies depending on tyre size, but I generally put 30ml in roadie tyres, 60ml in 26x2.1" MTB tyres & up to about 90ml in 29" or fat MTB tyres.

[quoteTubeless is very appealing because you can repair punctures without taking it off. Which would make it much easier with the rear hub.
[/quote]
Sorta, but not quite. If it's a small puncture the sealant will "self heal" the tyre before you even realise you've punctured. If it's a bigger slice that the sealant can't deal with it's just like a normal tyre; remove the tubeless valve & fit a tube. If it's a big enough hole, chuck a patch or tyre boot over it just as you would with a tubed tyre.
I had a thought, but it got run over as it crossed my mind.

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Re: BMC AC01 off road

Postby Duck! » Fri Apr 28, 2017 6:50 pm

CycloTron wrote:So, tubeless setups require sealant inside the tire which stops air from leaking and plugs small punctures on the go. The sealant eventually evaporates and will need to be replenished. You may need to do this around every 6-12 weeks months or so,

Fixed it. :wink:
I had a thought, but it got run over as it crossed my mind.

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Re: BMC AC01 off road

Postby CycloTron » Mon May 01, 2017 8:52 am

Duck! wrote:
CycloTron wrote:So, tubeless setups require sealant inside the tire which stops air from leaking and plugs small punctures on the go. The sealant eventually evaporates and will need to be replenished. You may need to do this around every 6-12 weeks months or so,

Fixed it. :wink:


Thanks Duck!

That's good to know. I've only been on the tubeless for about 4 months and you're right, every time I check, there's still sealant there, even though the manufacturer (Orange Seal) says the average life of the sealant is 30-45 days.

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