Not long now... should probably start training...

Easiest way to get your mileage up will be to add some extra to your commute so say make the commute in or home 15 miles which will take you about twice as long and so should be achievable now after 3 months of solid commuting. You would only need to this once a week (mid week would be good). You will need to do a longer weekend ride just to get yourself used riding longer and to work out what energy drinks and food works best for you.

See how your 15 miler on your commute goes and if it is was comfortable enough aim for 20 miles on the weekend. You have enough weeks to build you so you can start at 20 then go 25 then 30 say every other week. If you can do a 30-35 mile ride before your event you will be good for the 50 on the day however if you training is going well don't be afraid to add a few extra miles but don't over do it and make sure you have 1 or 2 rest days (one completely off the bike and the other a very easy cycle commute and I mean easy - you will feel as though you are not going anywhere but this is important in allowing your body the time it needs to adapt to the increased workload and to give it chance to grow stronger.

gtr mart wrote:

if you did nothing you would get round the 50 miles - it would just hurt and take w while.
I dont think you need to panic about getting into a massive training regime

exactly! hundreds of people will have done the recent manchester > blackpool [60 miles] without any training.

I found the same with the Norwich 50.

I averaged 15 miles per hour and it took 3 hours 12 mins on MTB with slicks. I was surprised that I was passing most people at that speed but as others have said alot of people will only do one charity event and dont train at all, they are not intersted in their time just that they enjoy their day out.

Me, I just want to do it as fast as I could.

As I said in my ealier post I bought a Camalbak and whilst this is great it will give you a back ache if your not used to wearing it. If you can avoid better to take bottles and stash things in rear pockets or underseat bag.

Which event are you doing?

I did one of these last May. I turned up with a road bike kitted out with a 52/39 chainset and a 12-25 cassette. Then I find out the course was set by a well-known MTBer. I was faced with my very own Paris-Roubaix ! It was great fun - fantastic countryside, extremely variable roads/tracks, rapidly wearing brakes and a variety of company - speed merchants, sloggers, born-again bikers etc. Good weather helped.
This was 65 miles and far further than what I normally did as 'training'. It also included some reasonably horrible hill sections which killed me in the morning and resulted in a bit of 'pushing' in the afternoon.
I realised that up until then I had generally been pissing about as a rider. So I resolved to i) go farther out (for more miles in the legs) when training; ii) go more slowly (I tend to 'blast' from beginning to end) and use the rest position in the middle of the bars, rather than always be on the hoods; iii) seriously work out hydration and nutrition when on the bike (I used to have 1 bottle of water - that was it...and I sweat like a b----d).
So now I am doing double the milage, 3-4 times a week with rest days, I take 50:50 apple juice/water with a touch of both salt (sodium) and 'low-salt' (potassium) added - 2 bottles, I used Boots-own dextrose+Vit C tabs as a boost. If I am out even further, say at the w/e, then I take a couple of Tracker bars or a fruit bar.
As regards kit, I changed to a 50/34 chainset. This meant that for my speed and cadence I was no longer 'double-shifting' all the time and could use the outer ring all day until I get to something seriously sloping, where I nowI have 2 extra bottom gears to help.
For the record, I am 53, top-heavy and no longer eating bread and dripping before I go out...
If you are doing the Stratford run in September, I am on the cheap Bianchi, in a blue jersey! See you there and good luck