Pacing a 100-mile bike race with Xert

Hi all
At the end of this month I’m racing Ride-London. That’s a 100-mile road race in very large groups (tens of thousands of entrants grouped by claimed ability). The course is undulating with, I think only 1000m of ‘climbing’

I want to do a maximal time which will clearly involve drafting and I have done this sort of thing before but am not an expert.

I’ve got some good data in Xert and I trust it to be about right for anything less than 3 hours.

My stats according to Xert are: TP 252w, 2 hour power 244w, lower TP 213w. age 56, weight 73kg, decent kit.

I think my TP is probably 15w lower than that in reality and maybe also my lower TP is 200w. If I did a traditional FTP test I think it would come out between 260w and 265w

However this ‘race’ may well involve lots of 5 minute bursts to keep up and when losing the draft on the hills after several hours the burst and hills will definitely take their toll even if i keep them to below threshold levels.

I did 100-miles at the weekend and i can do the distance. just maybe not at a modelled maximal effort

My plan without the help of xert will be to try to keep average power and NP at about 200w.

I’m thinking I can do it in 5 hours give or take 15 minutes.

A mate (who is better than me) is aiming for 4:30:00 and plans to just hold on.

So my question.
Q: which Xert CIQ tool can I use to pace this, if any?

and/or an other pacing advice

thank you

Not sure the Xert datafields really help pacing over that distance - they are more for knowing when you are about to reach your limit for efforts above threshold, rather than the (well-) below threshold efforts you will be doing. You could use fat / carbs for fueling but would test it out before as not everyone finds it that accurate. Otherwise I’d just pick a power target and stick to as much as possible, using judgement as to whether going over threshold to stay with the bunch is worth the effort (and the effort still shouldn’t be anywhere near breakthrough territory).

Re: power targets, I’m not quite clear on where you think your threshold is as on the one had you say 15w below 252w, but on the other hand you say 265w from an FTP test? If it’s the lower number than 200w for 5 hours sounds incredibly tough. Even at the higher threshold that’s more than 75% of threshold which sounds tough to me (but then I’m not an ultra endurance athlete). What power do you normally ride at for long endurance rides? What power did you do for you last 100-mile ride and how long did that take?