Anyone riding Audax on a Mercury?

[PH]

EDIT - Thread resurrected January 2023, skip straight to that if you like
http://thorncyclesforum.co.uk/index.php?topic=12866.msg111023#msg111023


The question in the title really.
If you are, what did you ride before and how does it compare? How do you have it set up?
I'm in a bit of a quandary, I bought the Mercury with the intention of using it partly to replace my Audax bike.  But having ridden 4 200s I'm not sure it will, there hasn't been any problem, it's certainly comfortable, but the times have been well down on what I would have expected on those routes in those conditions and I've dropped out of a couple of groups I'd have expected to stay with.  I have a few longer and hillier ones booked in over the next two months, and if I'm not going to use the Merc I need to spend money on the Audax to get it ready.  My Mercury isn't the lightest build, I could shave maybe 1.5 kg off it, lighter tyres and tubes (Which I'll probably do for the summer anyway) change the rack, maybe a different saddle, swap the Carradice saddlebag... but I don't want to be spending money on both bikes!  I'm still a little irritated that it isn't designed with separate rack and mudguard fittings, for a bike intended to be so versatile being able to drop the rack on and off without effecting the guards ought to be straightforward. 
Anyway, your thoughts appreciated, particularly if you have direct experience of the subject.
Thanks

[Danneaux]

I'm still a little irritated that it isn't designed with separate rack and mudguard fittings, for a bike intended to be so versatile being able to drop the rack on and off without effecting the guards ought to be straightforward. 

Hi Paul,

I realize this won't answer your primary question, but I do have a suggestion that may prove helpful with co-locating the rear rack and mudguard stays -- and making it possible to quickly remove or mount the rack without disturbing the mudguards:

If you take a threaded M5 (5mm x 0.8mm) threaded bolt and cut off the head, you'll have a threaded stud. Finish the cut end and fit two nuts jammed against each other to make a temporary head to screw the stud into place. I'd suggest some blue (medium) thread locking compound on the boss where the stud screws in, but it is not strictly necessary because a jam nut will hold it is place -- unscrew the outer nut and thread the inner nut so it jams against the shoulder of the threaded boss. You now have a mounting stud.

Place the mudguard eye(s) onto the stud first and secure using a stainless washer and nylock nut.

Now, you can attach or remove your rack easily by fitting its mounting eyes over the exposed stud, securing it in place using another washer and nylock nut. When the rack is not present, the mudguards will stay in place and you can use a presta valve nut to cover the exposed stud threads to avoid injury. You will need to manually spread/stretch/pull the rack ends apart slightly to fit over the studs, but it is elastic enough to spring back once it is mounted of you fit one leg at a time.

I have used this setup for many years on one of my bikes and it has worked fine so long as the rack load is reasonable, though I've never had problems with stud fracture or nut loosening while carrying as much as 15kg on the rack.
=====
Please (prompted by curiosity), what do your Audax and Mercury weigh dry when outfitted for Audax rides?

Best,

Dan.

[PH]

Thanks Dan, a decent shout, I may go down that route, though the rack spaced out further than necessary isn't ideal but acceptable for the loads I carry.  It's certainly a more economical solution than spending £££s on a titanium rack!

Please (prompted by curiosity), what do your Audax and Mercury weigh dry when outfitted for Audax rides?

My Audax bike is a SOMA ES, Tange frame & forks, Campag 9speed triple, 28mm tyres, guards - ready to ride 10.6 kg
The Merc, is currently 13.8 kg - it's not a fair comparison, as above it could shed between 1.5 and 2 kg depending on the rack solution. 

There's always going to be around 1 kg difference, Rohloff, wider rims & tyres, EBB, dynamo system, so the crux of my question is will that bring them close enough not to matter, or is it something other than the weight that makes the Merc a less suitable bike.
The ideal answer is of course suck it and see, and that may prove the only answer.  In practical terms that means spending money on the Audax bike when it would be easier to sell the frameset and keep the parts as spares for another bike, and spending money lightening the Merc which will have been unnecessary if I then don't Audax on it.... 

[martinf]

My Mercury isn't the lightest build, I could shave maybe 1.5 kg off it, lighter tyres and tubes (Which I'll probably do for the summer anyway)

I don't do Audax, but I have done a similar style of riding for "training" purposes.

If you intend to put lighter tyres and tubes on your Mercury anyway, I would advise doing that without spending money on any other modifications, then doing a few back-to back training rides to compare your Audax and your Mercury over the same circuit.

I did this kind of thing a few years ago for 2 separate reasons:

1 - to see whether fitting a Chainglider made any appreciable difference to efficiency. I was very sceptical about the way the Chainglider rubs on chain, sprocket and chainring. A few timed rides before and after fitting the Chainglider to my old utilty bike led me to conclude that it made no real difference, despite the sub-optimal setup (thick TA alloy chainring and 1/8" chain). Average speed for 4 x 25 kms without chainglider 24.0 kph, for 4 x 25 kms with chainglider 23.99 kph.

2 - to try and see whether a Rohloff would be significantly less efficient than a similar wide range derailleur system for loaded touring. To do this, I cleaned the wide range derailleur system on my old "heavy tourer" and did a few timed rides round my moderately hilly approx 50 km training loop.  I then converted the bike to use a (new) Nexus 8 Premium hub gear (without changing anything else apart from the transmission, gear shifters and rear wheel) and repeated the test rides a few times.
My expectation before doing the rides was for the derailleur setup to be more efficient, but for 5 circuits with derailleur gears followed by 5 circuits with the hub gear I found no significant difference, average speed was very close to 24 kph for both setups.   

After doing the tests, I flushed out the original grease from the Nexus 8 and lubricated it with synthetic gearbox oil. I have no figures to back this up, but I believe this improves the efficiency of the Nexus 8 Premium hub. Combined with running-in (gearboxes usually improve after a certain amount of use) I am reasonably convinced that there is no significant difference in efficiency between Nexus 8 Premium and wide range derailleur gears for my type of riding over moderately hilly terrain.

Caveat - I used a Shimano Nexus 8 Premium and not a Rohloff for my tests. It is possible that the Rohloff may be inherently less efficient than the Nexus, or (more probable IMO) it may require more "running in".

Round the same circuit, my best consistent performer was my lightweight 700C derailleur bike with supple Michelin Dynamic 28 mm tyres, and weighing several kg less than my "heavy tourer). Average speed for 26 circuits 25.19 kph. I used the lightweight 700C bike most as my aim was to get at least 2,000 kms of training before doing my Spain tour in 2011.

I did manage to beat this (for 1 circuit) using a cramped aerodynamic position (hands on the low part of the P-bars) on my hub geared Brompton, speed 25.89 kph. Not at all significant, and much less comfortable than using drop bars, but it reinforced my belief that aerodynamics and tyres (the Brompton had lightweight Kevlar-bead Kojak tyres) are the most important variables to play with if increased speed is the aim.

Before that, to liven up my daily commute in 2004 (22 kms each way at the time), I had already done some back-to-back tests comparing several different bikes and playing around with different tyres and handlebar configurations.

The 2 biggest factors I found that affected average speed were riding position (drop bars significantly faster than straight or roadster bars) and tyres (lightweight tyres with supple sidewalls significantly faster than tyres with thick sidewalls).

The only significant gearing conclusion I reached was that the Shimano Nexus 7 was significantly slower than the old Sturmey-Archer oil-lubricated S5-2 five speed hub gear. The Nexus 7 is reputed to be relatively inefficient compared to other hub gears. The Nexus 7 improved slightly after a bit of running in, and after I relubricated it with a low-viscosity grease.

Comparing two rather similar straight-bar bikes, one with derailleur gears and the other with a Sturmey-Archer oil-lubricated S5-2 five speed hub gear, the respective average speeds were 24.19 for the derailleur and 23.69 for the hub gear, which I didn't consider as significant (there were other minor differences between the two bikes).

[jags]

good set of lightweight strong custom wheels with  compass tyres are the secret .

[PH]

Thanks all - as much as I'd like there to be an answer I think martinf has summed it up in that the only way to "know" is to test it extensively, no amount of thinking about it or talking is going to come up with a conclusion, though I'm still interested in other's experience.
I've just ordered the parts to make the SOMA roadworthy, money I didn't really want to spend and won't see back if I don't keep it, hey ho...
To even it up, I'll strip the Merc back a bit before using for Audax, rack and dynamo off, minimise luggage and just to please jags I'll stick an Open Pro front wheel on, though the budget doesn't run to Compass tyres.
I have 2,400 km of Audax booked in over the next four months, I'll try and use them 50/50 and see how I feel then.

[PH]

It is possible that the Rohloff may be inherently less efficient than the Nexus, or (more probable IMO) it may require more "running in".

My hub has at least 70,000 miles on it, I think it's probably run in

[Danneaux]

All good wishes as you move forward, Paul. Looking forward to the results.

Helpful to hear your bike weights also; thanks.

All the best,

Dan.

[aggs]

I used my mercury for 200km audax rides , running 28mm tyres and mudguards.
If I needed to carry items I started using the Alpkit type bike packing type saddle bag which fits behind the saddle in an aero position and took the rack off.
For touring I added additional alpkit bags for frame and stem, found them really useful.
I never really enjoyed riding in a group on this bike because of the gear changing , people following you cannot see you changing down and the way of taking the power off momentarily I was worried someone may run into the back of me, I was a lot more cautious in this scenario.
However its a great comfortable bike for audax, a normal gear set up is a bit more sporty and maybe that's what your missing.

I would think the more disc brakes that get used group riding could also cause problems at times , but that's another debate!!
If someone is feathering there brakes in a group its useful to see with your own eyes to back off some peddling slowly to avoid slowing too quickly.

I also think more oil frequent oil changes makes it more efficient , but I was never that bothered in that aspect when choosing to ride this bike , but my Thorn Sportif feels faster and makes me ride faster, so I went faster!!

Loosing some weight of the bike does help, but an efficient ( comfortable) aero position make much more difference esp over a long event. and that includes luggage considerations too.

I think the Roholf is designed for really long events/tours when reliability makes a real difference over its lack of sportiness, hence their use on Expedition bikes and commuting bikes, lots of use, high reliability and low maintenance required. 

[PH]

Thanks aggs, plenty to ponder there.  I know what you mean about group riding, there's also the difference in when and where to change gear, in a group I sometimes find I'm staying in a gear because it's too much trouble for anyone else to change for a couple of hundred meters... I'll sometimes drop slightly off the back on climbs, knowing I can change gear whenever the gradient varies when those on derailleurs will find a gear they can stay in and do just that. 
Time will tell

[aggs]

Sounds like you have lots of rides planned!!

I also found the Mercury better for night riding too , easy to change gears and not worry about front chain rings in the dark when your tired on an audax and forget if your in the big ring or not on the front!!

Have a fun summer!     

[mickeg]

On the flat, I have always found that tires and pressure of the tires are about 90 percent of the things you can change for improving bicycle speed.  My experience is that weight is not much of a factor on flat terrain.

And weight really only comes into the mix when you are on hilly terrain.  A heavy bike takes a lot longer to get up a hill.  A heavy bike will initially accelerate down the hill faster too, but since (1) the two bikes have similar terminal velocities down hill that is mostly controlled by aerodynamics, and (2) you might spend very little time descending compared to the total time spent ascending, the heavy bike ends up losing a substantial amount of time on hilly terrain.

I have no data on this, no specific references to cite, that is just my general observation.  Thus, I put little emphasis on weight on routes that are fairly flat, but worry more about weight when on hilly terrain. 

Thus, a year ago when I did a two week bike tour in Southern Florida where I think I was never more than 3 meters above mean sea level (except when I crossed over water on a bridge, second photo was one of many bridges), I had no concern about weight, see first photo of my loaded Sherpa.  But last month I did a van supported trip (my luggage and camping gear was hauled by vehicle for me) on very hilly terrain, so I took the lightest weight bike I had that also had gearing low enough to actually climb the hills.

[PH]

Well three Audax in three days, 207 km, 276 km, 205 km, the first and third DIYs with camping gear, the middle one "A Ride Called Quest" plus an extra 60 km to and from my campsite.  5,350 meters climbing over the three days, so not mountainous, but not flat either and as those in the UK will know a real scorcher, well at least by UK standards.
I still have some pondering to do, I didn't give the bike much thought while riding, there were times I'd have been better off on one of my other two, the tourer would have been better with the camping gear and the Audax on the day without.  Over the three days it was the right bike to use, though it'd be nice to lessen the differences.
It wasn't the only Rohloff on the organised ride, I noticed one in a group that went past, though just got a glimpse of the hub not the bike and didn't see it again, still glad to see I'm not the only one!

[aggs]

Wow, some riding.
I know how you feel.
I sold mine as I built mine as a lightweight bike and always wished I had built it a bit more heavy duty for slightly  heavier loads, I had LW wheels and road caliper brakes which restricted my max tyre size  , so at times the Mk 4  Tourer was the best option option, but at the time I had this in "gravel" spec so was stripped down and on more all round "slow" tyres for the off road sections and was a bit of a chore to put into Touring mode for the odd occasion, but the Mercury was not built for the camping stuff!
The Tourer will never ride as Sporty as the Mercury but its an amazing bike and so comfortable too.
So the Mercury is a good all rounder as long as the wheels/ brakes  can can take the load.
A Mercury as a heavier duty build would have probably great on gravel too, esp for training rides, but I did not know this at the time and could have probably specced it to suit this use and even put a disc on the back to save wheel wear.  ( 35mm minimum tyres , 40 mm even better but I was restricted by my road calipers)
I miss my Mercury now, but it was used to fund a proper gravel bike. ( non Thorn!!)   Which is amazing and well worth it in that repect!

In hindsight you buy a Mercury for long term use and training rides and the boring stuff like getting fit and just getting out in the weather , relish its  low maintenance and probably use in conditions that are wintery/dirty/or away from home for a while, on dirty minor roads  Use it as the bike set up with lights on , mudguards and reliable tyres.  Keep it and do not sell it is my advice.

The Audax set up light and fast for when your fit and for use in good weather, or for an event  , for smooth tarmac and when your clock watching!

They are similar , but not quite similar!!

All bikes are good!!

[PH]

OK - experiment over, I had this conversation with myself (Audax rides give one plenty of times for such things)
Is the SOMA a better Audax bike
Yes in some ways - it's around 20 min per 100 km faster and comfortable enough for it never to be an issue as long at it's on reasonable roads.
Then why aren't you using it for all the Audax rides?
Well, sometimes I need to carry camping gear or other luggage to the start and home again, I can't always be sure the roads won't be too rough, or muddy enough to clog the clearance on the guards and I can't always be bothered to spend the extra time on cleaning and maintenance.
So, how many times a year are you likely to use it?
About four
Do you have the space and inclination to keep a bike for a few rides a year?
Yes to the inclination, there's no doubt it's a great bike, but sadly no to the space.


And there's the answer, the frameset will be on it's way to a new owner this week, other bits I can't re-use are for sale, I'll use the proceeds to make the bikes I do have the best I can.