how big

[GinjaDave]

I have standard wheel rims on my z1000 a1 and want to know, what is the biggest tyre size I can fit on them, without hitting against the swing arm or chain, I was thinking of BT45's

[KWACKERZ1]

Mine runs a 130. on a 2.50 no probs. although recommended max is 120.
Here is a guide.

Permissible Rim Widths (Inches) Metric Width (mm.) Standard Width (in.) Standard Low Profile (in.) Alpha Numeric Codes
1.60, 1.85 70 2.75 - MG
1.60, 1.85 80 3.00 3.60 MH
1.60, 1.85 80 3.00 3.60 MH
1.85, 2.15 90 3.25 3.60 MJ
1.85, 2.15 90 3.50 4.10 ML
2.15, 2.50 100 3.75 4.10 MM
2.15, 2.50, 2.75 110 4.00 4.60 MN
2.15, 2.50, 2.75 110 4.25 4.25/85 MP
2.15, 2.50, 2.75 120 4.50 4.25/85 MR
2.15, 2.50, 2.75 120 4.75 5.10 MS
2.50, 2.75, 3.00 130 5.00 5.10 MT
2.75, 3.00, 3.50 140 5.50 - MU
3.00, 3.50 150 6.00 - MW
3.00, 3.50, 4.00 160 - - -

[zed1015]

Don't go any wider than the recommended fitment for the width of the rim or you will bugger up the handling even worse than standard especially when cornering.

[zpower]

Get central wheels to put a bigger rim on it for you.

[tlc]

Go for standard size 4.00 and 3.25. When the guys at the bike meet point out how skinny your tyres are yet you ride circles round them out on the road you can tell us here and we'll all laugh with you.