BMC URS tyre clearance

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Nohands83
Posts: 259
Joined: Tue Feb 13, 2018 7:41 am
Location: Leeds, UK

by Nohands83

I know the URS has officially got clearance got a 45mm tyre but in the all images I've seen it looks really tight even with a 40mm tyre - one of the reviews specifically mentions this as well.
Before I hit the buy button would be great to hear from current owners their experience of this?

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SeanOB
Posts: 3
Joined: Thu Dec 23, 2021 7:30 pm
Location: New England, USA

by SeanOB

If I could ask for one change to the URS, it would be for more tyre clearance. However, before you make up your mind based on that statement alone, let me try to give you a few more details.

My URS came equipped with 7000x42 WTB Resolutes, which measure 44mm wide on the stock rims. They clear, but I wouldn't want to use that combination for serious mud-plugging, chainstay clearance being the limiting factor.

Instead, I typically run nominal 700x38 Gravelking slicks, which measure 40mm wide and have ample clearance. Indeed, if mud clearance isn't an important requirement (and I know it's never muddy near Leeds ;-) ), 44mm slicks would make maximum use of the available clearance.

When I'm heading for roughstuff and mud, I swap in 650Bs. Specifically, Terrene Elwoods, which measure 47mm wide on my rims, are as wide as I want to fit between the chainstays. A 52mm wide 650B knobbly tyre tyre will turn, but with zero margin. The fork, on the other hand, will take a 52mm wide 650B with plenty of mud clearance.

If you want to run mudguards (although I know it never rains in Leeds), I think 700x35 slicks might be the limit for good radial clearance, with radial clearance in the fork being the limiting factor. Instead, I again run 650Bs with 'guards, which allows me to run 47s with ample clearance. Oh, and the toe room which comes with the URS' geometry is brilliant!

Unfortunately, having mentioned 650B's several times, the situation could be even better. The left hand (non-drive, if you prefer) chainstay goes straight back from the bottom bracket (i.e. parallel to the frame's centreline) instead of flaring out, which could net a substantial increase in clearance, especially for smaller diameter 650B tyres. Presumably, they do this to clear something like a Stages power meter, but it was an unfortunate choice, IMHO. The right hand/drive chainstay curves around the tyre, offering a little more tyre clearance and ample chainring clearance. Indeed, given that the URS is 1x specific, it would have been nice if they maximised tyre clearance for use with a GRX crank, or similar, with its wider chainline.

Moving onto the bike itself, in general, it is an absolute joy to ride. The geometry and handling are simply eye-opening, coming from a more road-oriented gravel bike. The confidence that the combination of long front centre and reach, short stem and slack head angle bring to the table, is just joyful! Meanwhile, the elastomer rear suspension and compliant seatpost also make for a supremely comfortable ride. However, while all the above beg you to go downhill fast, if your downhills are rocky, your rims may beg for wider tyres. Or, perhaps it's time to investigate foam inserts!

I hope that helps.

rjich
Posts: 108
Joined: Sun Apr 11, 2021 11:38 am
Location: NYC, NY

by rjich

I see BMC released a new one too with a front shock if that helps. Similar clearance but maybe sends prices down.

https://www.bikeradar.com/news/2022-bmc-urs-lt/

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Nohands83
Posts: 259
Joined: Tue Feb 13, 2018 7:41 am
Location: Leeds, UK

by Nohands83

Thanks so much for your reply - really useful, confirmed a few of my suspicions - some positive (the handling), Some negative (the clearance).

The clearance sounds like similar situation to my current ride - Was hoping to avoid the 650b route as that’s what I’ve ended up doing at the moment.

The chainstay does sound like a strange design decision, particularly given the geometry and intended use.

Ha yes it never rains here and there’s definitely no mud - my local route choices are currently significantly reduced!

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