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What size tyres fit on this rim: ETRTO 622-18?

Discussion in 'Technical Know How' started by CopperCyclist, 7 Sep 2011.

  1. CopperCyclist

    CopperCyclist Über Member

    I have a Boardman Cyclocross, with Ritchey Disc OCR rims. Theres a sticker on the rims that reads ETRTO 622-18. I've currently got 700x32 Continental CityRide tyres on it, but I'd like to fit some thinner road tyres on it.

    However, despite searching on the net, the ETRTO stuff just has me massively confused. There also seem to be disagreement with different sites about what will fit on what.

    Does the 18 in the ETRTO number mean the thinner width I can go for is 18" or is this a faux pas and is my actual minimum wide some way higher?

    Hoping someone can assist!
     
  2. 2Loose

    2Loose Über Member

    Location:
    Nottingham
    You'll get 700x23 on there with no problems and I can't see why you would want anything thinner tbh.
    Hope that helps.
     
  3. Fiona N

    Fiona N Well-Known Member

    The '18' in the ETRTO number is the rim width in mm. Like 2Loose says, a 700 x 23 will fit :biggrin:
     
  4. 18 is the width of your rim (I think its the inner one) sheldon explains and the table at the bottom summarises it, it look likes the narrowest you can go safely is 25mm.
     
  5. Fiona N

    Fiona N Well-Known Member

    Well I did say 23mm would fit not that they'd be comfortable (I'm not sure safety's an issue, it's the likelihood of getting pinches and damaging the rim rather than blowing off which you get with wide tyres on a narrow rim) as you'd need to pump them up hard - hence :biggrin:
     
  6. I think Sheldon does admit some where that his table does err on the side of caution but surely the safety of not having your teeth shake out on 23mm is important :biggrin:
     
  7. 2Loose

    2Loose Über Member

    Location:
    Nottingham
    :rofl:
     
  8. CopperCyclist

    CopperCyclist Über Member

    I was hoping for a 23 anyway, so think I'll give it a go - thanks for the info!
     
  9. Zoiders

    Zoiders Guest

    Location:
    Ice Station Zebra
    If it looks right it usually is right, you can often see when a tyre is simply too slim for that width of rim to safely resist pinch punctures like Fiona describes.

    Don't get hung up on ETRTO - go into a shop and start quoting ETRTO numbers and they will look at you like you are a complete anorak.

    With a crosser I would keep it around the 25mm mark as the rims are just that bit broader than a comparable road wheelset, 23mm will run but you are risking dented rims if you strike raised iron work in the road. The old 27"X1"1/14 tyre was used for ages for all sorts of riding in britain because it was a good compromise between speed and durabilty so you should have no problems with a modern 25mm tyre or upwards.
     
  10. bromptonfb

    bromptonfb 2014 S2L Berrocco Brompton, 2013 S6R and 2012 S4L.

    it is very very important you know whether it's inside 18mm or outside 18mm. guessing' no good. and just because the bike came (if it did?) with 32mm means it's right. my fixie rims will fit 35mm spikes, but the max i should have on after measuring is 28mm, could have been nasty. it also explains why my marathon+'s blew off the rims whilst sat in the garage.
     
  11. CopperCyclist

    CopperCyclist Über Member

    The bike came with larger tyres still - obviouly cylocross ones - I believe, but would have to double check they were 35's, Ritchey Excavaders. My long term plan (think a year plus) is to have a road-bike for the dry days, and a cyclocross for the wet days, but in the meantime I've gone for a cyclocross, but with slicker tyres, not knobblies as the best (or worst!) of both worlds. I bought the CityRide 32’s simply because they were what was in the store at the time, but I think I could go thinner until, I get a road bike.

    That said, coming up to the winter months its probably more sensible to leave the 32's on... however I've convinced myself to bang the thinnest tyres I can n the cyclocross, and hop back on my old mountain bike if the weather is really, really bad.

    Many thanks for all the advice. I think I'll probaly end up playing safe and going for the 25mm. Everyone agrees they'll fit safely, and they will certainly be a decent amount thinner than my 32's anyway.
     
  12. Alun

    Alun Über Member

    Location:
    Liverpool
    I put 28mm Conti Ultra Gatorskins on my CX they're pretty fast, but will still cope with some poor surfaces. I run them at 100 psi.
     
  13. the_mikey

    the_mikey Tea master

    I'd say no lower than 25mm.
     
  14. 2Loose

    2Loose Über Member

    Location:
    Nottingham
    I agree, although the 23's will fit, the 25's would be more reliable on our roads, as well as more comfortable for the same speed. I can't tell the difference between my last 25's and current 23's in average speeds anyway, but the 25's were definitely slightly more comfortable with some of the local moon surface roads. Better to play it safe.
     
  15. Will1985

    Will1985 Über Member

    Location:
    South Norfolk
    I think HED and Zipp would disagree with the comments about using 23mm tyres on these rims - their latest rims are 19mm ETRTO and ride very nicely. I wouldn't put anything less than a 22mm Conti Attack on them though.
     
  16. Zoiders

    Zoiders Guest

    Location:
    Ice Station Zebra
    HED and Zipp aren't really marketing towards the commuter or clubman rider on UK roads though are they?
     
  17. RecordAceFromNew

    RecordAceFromNew Swinging Member

    Location:
    West London
    The most comprehensive document on the subject I have seen is this. It is practically certain that your rim is crochet-type, meaning it is 622-18c (18mm internal rim width), so tyre width north of 25mm would be consistent with ISO 5775, fwiw.

    However the above hasn't stopped me using 20mm tyres on 622-15.5c rims (which have 20mm nominal external width) - operating tyre widths (and pressures) from 19mm to 25mm (137psi to 104psi) are suggested by the manufacturer.
     
  18. Will1985

    Will1985 Über Member

    Location:
    South Norfolk
    There were the same fears about pinch flats when the wider rims first came out, but people have found they are fine. I've not had any in the 10 months of ownership, unlike numerous pinch flats on my Campag wheels over the years....that's my n=1 experience anyway.