GridIron on a recumbent

DIscuss anything relating to non-standard cycles and their equipment.
Post Reply
UpWrong
Posts: 2409
Joined: 31 May 2009, 12:16pm
Location: Portsmouth, Hampshire

GridIron on a recumbent

Post by UpWrong »

Sunday 8th October I did the New Forest Gridron for the first time, a 100Km plus ride, on my RANS Stratus XP. It was lovely weather and a great ride. I set off quite late around 09:30 after taking a while to extricate the bike from the car and re-assemble it. As you may know, it's a relaxed ride where the main challenge for those of us without a GPS is following the route sheet. I kept with a couple of riders who had a Garmin for most of the 40K to the first checkpoint which was a bit parasitical of me. After the checkpoint I made my own way and had to keep stopping to check which was just as weill because I went rather wrong for a mile or so at one point.

A friend who started at 10:30 caught me a bit before the second checkpoint around 70K which was closing as we reached it. We then carried on together to the finish, arriving around 5:40 I think.

Highly recommended. I didn't see any other bent riders but subsequent photos show a guy on a white Challenge Furai I think. Next time I'll get going earlier and will swap a tail bag for the pannier and look to lean the seat back a bit more. I seemed to be at an Aero disadvantage to my mate on a Roberts Audax bike with no mudguards.
Geoff.D
Posts: 1982
Joined: 12 Mar 2010, 9:20pm

Re: GridIron on a recumbent

Post by Geoff.D »

UpWrong wrote:Highly recommended. I didn't see any other bent riders but subsequent photos show a guy on a white Challenge Furai I think. Next time I'll get going earlier and will swap a tail bag for the pannier and look to lean the seat back a bit more. I seemed to be at an Aero disadvantage to my mate on a Roberts Audax bike with no mudguards.


Sounds like you had a good day out, UpWrong. Whenever I've done a sportive on my trike I've come in with a grin and pleasant memories.

I'd like to ask you about your feeling that you were "....at an Aero disadvantage to my mate on a Roberts Audax....". How did you come to that conclusion? On the road I can imagine that a simple test would be your relative accelerations down the same hill whilst you're both freewheeling. But, there are other factors other than aero disadvantage (tyres, wheel size to road surface, etc). And, of course, your engines might not be the same :wink:
User avatar
Tigerbiten
Posts: 2503
Joined: 29 Jun 2009, 6:49am

Re: GridIron on a recumbent

Post by Tigerbiten »

Geoff.D wrote:I'd like to ask you about your feeling that you were "....at an Aero disadvantage to my mate on a Roberts Audax....".

The picture I've found on the internet show that RANS Stratus XP is a very crank forward type of recumbentbent.
So LWB with low BB behind the front wheel and an upright seat.
That type of bent tends to be easy to ride/balance but it's not the most aero position.
An upwrong rider in a downhill tuck will probably have an advantage.
So dropping the seat back will probably help.

The tail bag will be more aero that the pannier, unless it won't fit with the seat tipped back.
If you just need a little bit more storage space, look at the frame bags that can be fitted to MTB's.
Geoff.D
Posts: 1982
Joined: 12 Mar 2010, 9:20pm

Re: GridIron on a recumbent

Post by Geoff.D »

I ask the question because many years ago I did some comparisons between my upright and my recumbent bikes. I used a hill of about 1 Km in length (IIRC). Started off from the same point on each run, with a half turn of the cranks and freewheeling thereafter. I did 3 runs of each and took an average. I'd made a rear and a front fairing of grp for the recumbent, and did runs in a variety of assembly.

I have stable of results, but unfortunately it won't copy as a table. However, one set of results was -

Dawes Galaxy - sitting upright - max speed - 24.3mph
Dawes Galaxy - nose on bars - max speed - 29.2
Recumbent . - naked - max speed - 35.2
Recumbent - rear fairing. - max speed - 37.3
Recumbent. - front fairing. - max speed - 36.4
Recumbent. - both fairings. - max speed - 39.3

There's absolutely nothing remarkable about this set of results. Both fairings are the best, but not that much better than simply having a rear fairing. "Nose on bars" is a significant improvement on sitting upright on the Galaxy, and brings it somewhere near the results for the recumbent. But, of course, "nose on bars" isn't a sustainable position in general.
Last edited by Geoff.D on 20 Oct 2017, 9:03am, edited 1 time in total.
UpWrong
Posts: 2409
Joined: 31 May 2009, 12:16pm
Location: Portsmouth, Hampshire

Re: GridIron on a recumbent

Post by UpWrong »

He was coasting on the Roberts whilst I was still pedalling, although when behind he would have been getting a tow. The RANS has two 26" wheels, the Roberts 700c wheels some some of the advantage was probably less rolling resistance. All up weight was probably similar.

I had left my front mudguard off because it was a dry day, just wish I'd use a tail bag instead of the pannier. I also had frame bag mounted transversely across the chopper bars where I kept the route sheet and my phone. I suspect that added drag although it was angled to form a fabric fairing.

I had no aches the next day whatsoever which illustrates the advantage of riding bent. If I'd been on my Thorn Audax then I'd still be aching 48 or even 72 hours later.
User avatar
squeaker
Posts: 4112
Joined: 12 Jan 2007, 11:43pm
Location: Sussex

Re: GridIron on a recumbent

Post by squeaker »

Agree that pannier bag(s) are a right (aero) drag on a 'bent (compared with a tailbag) based on limited tests with my Grasshopper.
Pleased you had an enjoyable Gridiron :)
"42"
Post Reply