smallest chainring onto an old school spider

[gary4130]

does anybody know what the smallest size chainring that would fit onto a spider ? and does it need to be a particular size ,have seen a few on e-bay for road bikes, would these stiil fit?

[Mattdub]

39 tooth was used on cruisers bitd 

[HEYWOOD BMX]

  Check that the bolt holes match up with the spider.Most BMX stuff is 110 BCD,road/MTB is often 104 BCD?

[Gary72]

39 will fit on, but no lower as the arms are right next to the chain on a 39. run it with 14

[bobafett]

Check that the bolt holes match up with the spider.Most BMX stuff is 110 BCD,road/MTB is often 104 BCD?

And even then it depends what spider you've got - I know takagi / tioga spider's can't be used with the likes of a sugino ring (unless it's the slotted hole version of the spider) bloody mine field  

[HEYWOOD BMX]

MCS do a 34t/5 hole sprocket....

[gary4130]

MCS do a 34t/5 hole sprocket....

yeah thats the one i saw was going to go for a 35 or 36 t 'ring ,but didnt want to shell out £13 if doesnt fit ,but says bmx so might be ok

[gary4130]

39 will fit on, but no lower as the arms are right next to the chain on a 39. run it with 14

cheers gary ,have already 39/14 but wanted to go smaller if poss ,35/13 or 36/13 i think might be the lowest that will fit

[gary4130]

got a 34t 110 bcd off the bay and fits on the spider no probs and the chain clearance is ok,thanks to all for your help .
the grearing at the mo is 34/13 which is about equal to 42/16 so its not too bad,just need to find a 35 or 36 now.