Just about to buy some new tyres, something I can leave on all year round as I can’t be bothered with all the messing about changing tyres to suit conditions anymore. Most of my tyres have been around the 600g mark. Just noticed the WTB prowler XTs on CRC which seem like a bargain, but they are 848g. Gonna be putting nearly half a kg on the bike (which is built up light) at the wheels, will I honestly notice much difference?

Yes. Even I can when I swap tyres around

You will feel the difference but do you really care? I use adVantages 2.5″ all year round, all they do is slowing me down on the uphills.

My Rocky Ridge came with WTB Prowlers and I found the v.draggy and I usually ride Kenda Nevegal 2.35!

2.25 nobby nics stay on my epiphany all year round

As above. You’ll feel it but the real effect is negligible.

Been proven, even TJ believes it.

On a light build you will notice a pound of extra weight on the wheels and it seems daft to put that much extra weight on a bike youve probably spent £££ building light.

Often its the drag from the grip/tread that is more noticeable than the weight. I had dual ply supertacky minions for the alps and left them on when I got back here. They weigh about 1kg a piece IIRC but they were so draggy whenever I was on tarmac or hardpack I stopped to check I didnt have a flat on the rear 😯

I was suprised how light Kenda Nevegals (~600g) are, compared to the standard minion I also now use (700g+).

If youre going mail order these guys are great, and were the cheapest when I last looked for a tyre (notwithstanding some OE blowout offer somewhere)

http://www.nextdaytyres.com/

TYre quality makes a big difference too.

I’ve been using this with a Stout 2.3 recently on the dry trails. I’d say they feel no more draggy than the 2.35 HR Maxxpro I’ve been using, probably less so as the profile is a little lower. If you are coming from a 500g tyre, you will notice it takes more kick to get up to speed. On the plus side, these tyres feel nicely cushioned when it gets rough.

I’m about to take some IRC Kujo 2.35″ off my bike to replace with some 2.35″ UST Prowlers. Going from 1300 grms to 850 grms I can save a lot of weight.

(Shame I’m still around 15 stone).

You will notice it yes, but not as much as you notice the draggy tread pattern or a soft compound. Tyre weight really only comes into effect when you’re accelerating, at a constant speed you’re not having to do any more work. A slow tread pattern and soft compound is always doing it’s best to sap your energy though…

Of course, within reason lighter is better yes, but I’d not agonise over 100g here or there myself. I’d be more worried about the tread pattern being appropriate, and how fast rolling the tyre is.