Scotland’s City and the Sgurr is a spicy new route that’s just right for hill repeats and tough climbing races. The route takes in both sides of the Sgurr climb; the longer side (Sgurr Summit North) is 1.6km long at 3.7%, while the shorter side (Sgurr Summit South) is 1km at 3.3%.
The climbs are really the focal points of the route. Everything else is just turnarounds and descents!
What makes it really interesting, though, is that the longer climb is mostly gravel. With different types of bikes rolling at different speeds on different surfaces, City and the Sgurr’s mixed-surface design leaves riders asking: which type of bike should I use for this course?
Our Test Bikes
To answer the question, we tested the route using six different frame/wheel combos and a solo rider (75kg) holding steady wattage (300W) with no drafting. Here are the bikes, in order of their performance on a flat, paved road:
- Cadex Tri + DT Swiss Disc wheels
- Specialized Venge S-Works + DT Swiss Disc wheels
- Tron Bike (Zwift Concept Z1)
- Specialized Aethos + Lightweight Meilenstein wheels
- Specialized Crux + Roval Terra CLX wheels (gravel bike)
- Scott Spark RC World Cup (mountain bike)
Results: Sgurr Summit North
This is the main climb on the route, so naturally we were curious how each bike would perform. Not surprisingly, the gravel bike (Crux) beat everyone else, hands-down.
|Frame + Wheelset||KOM Time|
|Specialized Crux + Rovals||4:04|
|Cadex Tri + DT Swiss Disc||4:22|
|Scott Spark RC World Cup (MTB)||4:22|
|Specialized Aethos + Lightweight Meilensteins||4:23|
|Specialized Venge S-Works + DT Swiss Disc||4:24|
Results: Sgurr Summit South
What about the paved side of the climb? Again, the results aren’t surprising – the road bikes won, and aero won the day:
|Frame + Wheelset||KOM Time|
|Cadex Tri + DT Swiss Disc||2:09|
|Specialized Venge S-Works + DT Swiss Disc||2:11|
|Specialized Aethos + Lightweight Meilensteins||2:12|
|Specialized Crux + Rovals||2:21|
|Scott Spark RC World Cup (MTB)||2:31|
The Venge and its heavy disc wheels edging out the Tron and Aethos may be surprising, but this can be attributed to a few factors:
- The climb is short, leaving already closely-matched frames without enough road to pull away from each other
- The climb isn’t very steep on this side, so aero abilities still matter
- Strava is only precise to the second, so the time difference could just be a rounding error
Results: Full City and Sgurr Course (Not Including Lead-In)
Now the big question: which setup is fastest over one lap of the course?
|Frame + Wheelset||Time|
|Cadex Tri + DT Swiss Disc||10:29|
|Specialized Crux + Rovals||10:37|
|Specialized Venge S-Works + DT Swiss Disc||10:43|
|Specialized Aethos + Lightweight Meilensteins||10:49|
|Scott Spark RC World Cup (MTB)||11:11|
Why did the Cadex Tri win? Because TT bikes on Zwift are much more aero than other frames. But in a race with drafting, a TT frame definitely isn’t your best choice.
In a drafting race, the Crux wins. Why? Do the math. The route is only 5.9km long, and that includes going up and down the 1.6km gravel climb. That’s ~3.2km of gravel, which means more than half the route is gravel.
If you include the lead-in, the gravel percentage actually increases to ~55% of the course. And in fact, if you include the lead-in, the Crux beats the Cadex Tri in a TT race by 2 seconds. Truth.
More to Consider
Hopefully, the timings above are a helpful guide when choosing your bike for the City and Sgurr route. But before you go, there are a few more things worth noting:
Watch the Finish
The last bit of the gravel climb is actually paved, so if you’re on a gravel bike racing riders on road bikes, you’ll want to shake them off your wheel before you get to the end.
Last Climb Counts
In a race, riders will generally save what they can and then go all-in on the final climb. That final climb is the gravel side, and you’ll probably want every advantage you can get for your last ascent of the Sgurr.
Based on the Crr numbers, gravel bike power savings is around 2x that of the road bike, when each bike is on its ideal surface.
Example: at 40kph a road bike saves 36W over gravel on pavement. But at that same speed on gravel, a gravel bike saves 66W over a road bike!
Bike Choice Doesn’t Matter (Much)
Don’t stress about using the exact same gravel or road bike setup as I did in my tests. The fastest gravel bike or fastest road bike you have access to will turn in very similar times. The biggest concern is the type of bike (road vs gravel).
Racing Tips: City and the Sgurr on a Gravel Bike
If you opt for a gravel bike on your next City and the Sgurr race, here’s how I would break up the race mentally in order to finish well against other gravel bike riders while dropping the roadies:
- Paved Lead-In (0-1.1km): Be ready to go hard for the first kilometer: Zwift race starts are always a bit spicy, but this will be extra hard for you since you’ll be trying to keep up with road bikes on pavement. Sit in the draft, hold a good position, and wait for the gravel before you attack.
- First Gravel Climb (1.1-2.6km): keep the pace high, but know that if you go off the front you’ll get pulled back by roadies on the paved descent and climb. Put the hurt on the road bikes if you can, or just maintain a good pack position if you’re struggling.
- Paved Descent (2.7-3.7km): normally you’d be recovering on the descent, but you may need to put in a bit of work to stay in the wheels of the road bikes. Try not to let them drop you, as you may never pull them back if they get too far away this early!
- Paved Climb (4.1-5.1km): this will be the most challenging part of the ride in terms of maintaining a good place in the peloton, since you’re fighting against advantaged road bikes. Grit your teeth, sit in the wheels, and push hard – you’ll be able to recover on the gravel descent just up the road.
- Gravel Descent (5.1-6.7km): probably the easiest part of your race, unless you’re needing to push to bridge across to groups ahead. If you’re in the front group you should be able to almost soft pedal here and get that heart rate down.
- Second Gravel Climb (7-8.6km): there’s probably carnage all over the race course, but this final climb is going to be extra brutal. If you’ve survived in the front pack, be sure to drop any roadies before the final paved ~100m to the line, so they don’t outsprint you. Mid-pack or near the back? See how many roadies you can catch before the top. Go for gravel glory!
Question or Comments?
Thanks a lot for that insight. Had no idea. See you on the route
I was told to draft. Drafting seemed to save a lot of time.
Fantastic research, testing and advice as always, Eric!!
A really great and detailed article and along the lines of what I was thinking. The Semi finals bike swapping discussion is going to be chaos
Not counting the descents (which is probably a bad choice to ignore on my part), at Eric’s speeds (mine are slower, so more savings gained by using the ideal bike), it looks like you could save ~50s on the climbs by using the ideal bike on each surface for a normal race of North-South-North (semifinals, all hell is going to break loose). Start on the gravel and switch at the top, that’s 2 swaps (though the lead-in will hurt). If I go slow and careful and don’t screw up something due to oxygen-deprived race-brain (about every other race involving a… Read more »
I was thinking this as well. But when will you switch back to gravel? At the top again or do gravel descent on road bike and switch to gravel just before the 2nd gravel climb. In this last case you have advantage on the tarmac after descent but indoor know how much you’ll
lose on descent…
I would say top again because you’re the slowest there and that would allow you to keep any momentum from the descent as you turn around and go back to the climb again.
you would never swap on this. its far too short and too easy a climb.
It might be interesting for fts….
Thanks for the analysis. I used the Specialized Venge +DT Swiss Disc on my first trip on this route last week. Nice to see my best guess was not half bad!
After two years to earn the Tron bike I’m sticking with it 🙂
Any advice for a TT on this course? Just stick with the fastest TT bike?
This is literally what the article tested. The answers are above.
I raced this and chose gravel, seemed obvious–slightly longer gravel climb vs paved climb but more importantly the final climb no matter how many laps is gonna be gravel and hard to imagine a roadie breakaway staying ahead for that.
Articles like this take a lot of effort on your part. Thanks for sharing!
It seems that the Roval gravel wheels mentioned in the test with the Crux don’t appear in the Drop Shop. Will they be available at some point? Peter J
It appears you have to select a gravel bike to outfit before you can choose the Roval gravel wheels.
I went to the Drop Shop to buy them. Didn’t see them in the Royal list. Was I wrong? I don’t see them in the wheels by level either. I’ll try again tomorrow.
You have to have a gravel bike equipped before you can see gravel wheels in the Drop Shop or your garage.
Thanks Eric…still learning…P
Eric, for itt on this route, gravel or cadex?
Use a TT bike. They’re almost always faster when there’s no drafting.
ZRL Semis race #1 will have drafting turned off and be a group start like their Duathlon series. I don’t know if TT bikes will be available, but I would hope so! Thanks for the test results Eric!
How do you know about the draft?
Drafting is on
but didn’t your results show that the Gravel setup is quicker? You chose 75kg at 300W riding individually (same as in the TT). I am planning on doing the TT City and Sgurr (incl. lead-in) later today and from the analysis I would assume Crux should defeat all others… What am I missing?
I didn’t test a TT bike… but they’re basically always faster, if it’s a non draft event.
Even if it’s pure gravel surface climb vs a gravel bike? Like say Sea to Tree?
Not sure there, Tim. I think it would be close.
Gravel will be faster on dirt.. Just did an ITT on jungle lead in.. The TT bike was about 15 sec faster until start dirt. But in the end it was close.. Dont think it was much in it. Have also done a test on sea to tree.. although TT wil beat gravel by 10s on tarmac, it became quite clear that gravel would win..
Would you be so kind? Would be interesting to know for pretty obvious reasons
Added the TT bike to the results above.
Wait, the TT bike is only 8 sec faster w/o lead-in for the full route, but the lead in includes full additional gravel climb where you’d gain presumably ~18s for gravel v. TT (similar to road bikes tested bc of slow speeds). Is a gravel bike really more than 10s slower on the 1.1km road part of the lead in? Seems like quite a close call rather than a clear win for TT bike. All of this is complicated further bc of pacing strategy for a fatty like me (90kg), who has to spend big watts on the hills to… Read more »
Actually just did a race on TT bike go test.. went back after the race and did the tarmac bit on gravel.. 10s slower. So sounds right.
Great post, Eric, thanks!
Perfect. I think the X factors are two fold ayou say them but for some in the middle zone it may be a hard call. 1) after the first 30sec hoe much the group eases amd again going up,south side. Huge but somewhat predictable. The rider: if they ARENT a front group rider then boom gravel bike EASY call. If one expects to nail and hold the front group then how hard they go and how close you are to your limit. Super strong rider easy call gravel bike. Front group but others often say more powerful (often my situation,.… Read more »
I actually gambled this would be the case and happened to win the C race of last weekends Worlds Experience ride by quite a significant margin, but with a much lower 5 minute w/kg than the riders finishing after me (ZwiftPower – Zwift Insider Worlds Experience (2 of 3)). This whole margin was gained on the last ascent, which I started together with about 7 other riders. I did feel I had to push harder from the start gate and in the descent to the first climb, but the draft was good enough to hang on and I definitely felt the… Read more »
Alas 4 W/kg doesn’t mean much on a whole course that’s not pancake flat or all uphill, as it’s not a realistic pacing patern. I wonder if it’d be possible to have the same tests done, but say with a Red or Green robopacer pacing pattern ?
ITT on this route, TT bike or gravel bike? 🧐
TT bike for sure. See results of the CADEX Tri I just added to the post…
Did this course today as an iTT in C Cat on a TT bike and despite higher wattage and equal wkg I finished over 40 seconds behind the winner. Shouldn’t happen unless they had much better wheels or bike (gravel?)…Going to need to test this a bit more on my end before ZRL as something doesn’t feel right here.
Doing more avg watts is good, but you also have to put out the extra wattage when its most useful. If you put out higher watts then the other person on the downhills that’s pretty much a waste for example. IF you want more insight find the winners effort on strava and hit “compare” to see where you gained or lost time. I think this is only available on the desktop website, not mobile or app though.
Good shout! Had not used that feature before. Looks like it all came down to the last climb, as we were all effectively tied at the turnaround. Was about a 0.2 wkg difference going up, which over 5 minutes climbing would explain the the 20+ second gap.
Had I been on a gravel bike they likely would have been way ahead at the turnaround already, leading to an even worse result. Apparently I was blaming the bike choice when I should have blamed my poor climbing 😉
Alright, so here’s some more numbers to ponder – I rode a race on this today on a gravel bike for comparison. I know it’s not apples to apples as there was draft in this race and my wattage wasn’t exactly consistent on the two rides but gives you an idea of how things panned out by segment. 1st Time Summit North (Gravel Side): TT Bike – 5:00 (278w) Gravel – 3:59 (300w) Paved Descent: TT Bike – 1:17 (236w) Gravel – 1:19 (214w) Summit South (Paved Side): TT Bike – 2:24 (281w) Gravel – 2:38 (264w) Gravel Descent: TT… Read more »
Great article, thanks. Can you let us know the time difference on the dh sections as well? It would be interesting to see what it means at race pace, i.e. 5 w/kg uphill and 2 w/kg dh.
Thanks a lot, Eric! I love this test and i would be very keen of seeing such results for more routes. For the Sgurr it is an interesting mix of climb, descent and surface, but even the mix of climbs and flats would be of interest. For example, I rode Radha Risings Climbers Gambit yesterday and i was equipped with alpinist with hindsight of the Epic KOM. But i felt it was really hard to remain in the blob to even get to the Epic KOM. I was wondering if Cadex 65 wheels would have been better to stay aero… Read more »
Thanks as always for doing these analyses Eric. Question, as a 51kg rider, I wonder if there is a weight ratio penalty for using a heavier bike like the TT bikes when you are that small? I tend to ride the Scott Addict RC with the Millensteins on the assumption that it’s a lighter setup so a better weight ratio for me and it appears to be a fairly good all around choice based on your Frame Ranking article. Even though I can hang in fairly well on the flats, I get passed like I’m standing still on or shot… Read more »
Thanks, Eric. I’m wondering if you’ve considered this question.
Your tests are always (I think) at a constant wattage throughout the course. But in a race, riders are typically going to put down significantly higher power on the climbs than on the flats and descents.
So I’m guessing that that fact might give the gravel and lightweight bikes more of an advantage on this course than the constant wattage test indicates. Any thoughts?
Thanks for the great test and tips, Eric! Your insight got me the win in this week’s monthly racing series! Keep up the great work.
Hey Eric. Always a big thanks to you for these tests. As a 92kg C+ rider, I don’t really struggle sitting in on the flats, but hills, meh! So I take your analyses and typically skew toward selecting bikes that are “faster” on the climbs (where I feel I need the most “help”). Am I thinking the right way here for bike selection?
Yes, I think so! There are different ways to approach bike selection, but using the bike to shore up your weakest points is definitely a smart approach.