Perhaps I don’t understand what you mean by “side bars”
Could you explain some more or provide a picture?
Hi I tried to post a picture of it but it did not seem to upload … anyhow if you look at say the Giro empire mtb shoe on their site, and then look at the sole there is a raised rubber section that runs along the length of the area where you would attach the cleat to the shoe (along the outer edge of the fore foot of the shoe). These are on either side of the cleat. These are the bars I am referring to. Road shoes are a simple flat sole.
I use a pair of really old Nike road shoes on the trainer with SPD cleats and pedals (1990s shoes). There’s no issue doing that as far as riding. Walking on them is worse than with a regular road cleat though.
I switched to SPD pedals on all my bikes in the early 2000s. I use Shimano pedals as well as generic Nashbar SPDs. The Shimanos are much better in mud, but the Nashbar pedals are fine, especially on the road. I put my shoes on in T1 and do a cross mount going out and a cross dismount coming back into T2. Saves some time.
If you want a road like SPD pedal, Shimano makes several. A good review on CyclingTips for one of them: https://cyclingtips.com/2018/07/shimano-a600-pedal-review/